Filed Pursuant to Rule 424(b)(2)

Registration No. 333-220576

CALCULATION OF REGISTRATION FEE

PROSPECTUS SUPPLEMENT

TO PROSPECTUS DATED SEPTEMBER 22, 2017

8,000,000 Shares

5.850% Series K Cumulative Redeemable Preferred Stock

(Liquidation Preference $25.00 per share)

We are offering 8,000,000 shares of our 5.850% series K cumulative redeemable preferred stock, par value $0.01 per share, which we refer to in this prospectus supplement as the series K preferred stock. We will pay cumulative dividends on the series K preferred stock from the date of original issue at a rate of 5.850% per annum of the $25.00 liquidation preference per share (equivalent to an annual rate of $1.4625 per share). Dividends on the series K preferred stock will be payable quarterly in arrears on or about the last day of March, June, September and December of each year, beginning June 28, 2019. The series K preferred stock will rank on parity with our outstanding preferred stock and senior to our common stock with respect to dividend rights and rights upon our liquidation, dissolution or winding up.

Generally, we are not allowed to redeem the series K preferred stock prior to March 13, 2024 except in limited circumstances to preserve our status as a real estate investment trust, or REIT, and pursuant to the special optional redemption provision described below. On or after March 13, 2024 we may, at our option, redeem the series K preferred stock, in whole or in part, at any time or from time to time, for cash at a redemption price of $25.00 per share, plus all accrued and unpaid dividends on such series K preferred stock up to but excluding the redemption date. In addition, upon the occurrence of a change of control, as a result of which neither our common stock, par value $0.01 per share, nor the common securities of the acquiring or surviving entity (or American Depositary Receipts, or ADRs, representing such securities) is listed on the New York Stock Exchange, or NYSE, the NYSE MKT LLC, or the NYSE MKT, or the NASDAQ Stock Market, or NASDAQ, or listed or quoted on a successor exchange or quotation system, we may, at our option, redeem the series K preferred stock, in whole or in part within 120 days after the first date on which such change of control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If we exercise any of our redemption rights relating to the series K preferred stock, the holders of series K preferred stock will not have the conversion right described below. The series K preferred stock has no stated maturity and is not subject to mandatory redemption or any sinking fund. Holders of shares of the series K preferred stock will generally have no voting rights except for limited voting rights if we fail to pay dividends for six or more quarterly periods (whether or not consecutive) and in certain other circumstances.

Upon the occurrence of a change of control, as a result of which neither our common stock nor the common securities of the acquiring or surviving entity (or ADRs representing such securities) is listed on the NYSE, the NYSE MKT or NASDAQ or listed or quoted on a successor exchange or quotation system, each holder of series K preferred stock will have the right (unless, prior to the Change of Control Conversion Date (as defined herein), we have provided or provide notice of our election to redeem the series K preferred stock) to convert some or all of the series K preferred stock held by it into a number of shares of our common stock per share of series K preferred stock to be converted equal to the lesser of:

subject, in each case, to provisions for the receipt of alternative consideration as described in this prospectus supplement.

We are organized and conduct our operations to qualify as a REIT for federal income tax purposes. To assist us in complying with certain federal income tax requirements applicable to REITs, our charter contains certain restrictions relating to the ownership and transfer of our capital stock, including an ownership limit of 9.8% on the series K preferred stock.

No market currently exists for the series K preferred stock. We intend to file an application to list the series K preferred stock on the NYSE under the symbol “DLR Pr K”. If the application is approved, trading of the series K preferred stock on the NYSE is expected to commence within 30 days after the date of initial delivery of the series K preferred stock.

An investment in our series K preferred stock involves risks. See “Risk Factors” beginning on page S-20 of this prospectus supplement and page 3 of the accompanying prospectus for certain risk factors relevant to an investment in the series K preferred stock.

We have granted the underwriters an option to purchase up to an additional 1,200,000 shares of the series K preferred stock within 30 days from the date of this prospectus supplement solely to cover over-allotments.

The underwriters expect to deliver shares of the series K preferred stock through The Depository Trust Company on or about March 13, 2019.

Neither the United States Securities and Exchange Commission, or the SEC, nor any state securities commission has approved or disapproved of these securities, or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Joint Book-Running Managers

The date of this prospectus supplement is March 4, 2019.

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

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ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the terms of the offering of the series K preferred stock and also adds to and updates information contained in the accompanying prospectus as well as the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus, gives more general information about securities we may offer from time to time, some of which does not apply to the series K preferred stock we are offering. To the extent any inconsistency or conflict exists between the information included in this prospectus supplement and the information included in the accompanying prospectus, the information included or incorporated by reference in this prospectus supplement updates and supersedes the information in the accompanying prospectus. This prospectus supplement incorporates by reference important business and financial information about us that is not included in or delivered with this prospectus supplement.

It is important for you to read and consider all information contained in this prospectus supplement and the accompanying prospectus in making your investment decision. You should also read and consider the information contained in the documents identified under the heading “Where You Can Find More Information.”

Unless otherwise indicated or unless the context requires otherwise, all references in this prospectus supplement and the accompanying prospectus to “we,” “us,” “our,” “Digital Realty,” “the company” or “our company” refer to Digital Realty Trust, Inc. together with our consolidated subsidiaries, including Digital Realty Trust, L.P., a Maryland limited partnership, of which Digital Realty Trust, Inc. is the sole general partner and which we refer to in this prospectus supplement and the accompanying prospectus as “the operating partnership” or “our operating partnership.”

All references in this prospectus supplement to our operating partnership’s global revolving credit facility mean our operating partnership’s $2.35 billion senior unsecured revolving credit facility and global senior credit agreement, and all references in this prospectus supplement to our operating partnership’s term loan facility mean our operating partnership’s senior unsecured multi-currency term loan facility and term loan agreement, which governs a $300 million five-year senior unsecured term loan and a $512 million five-year senior unsecured term loan. All references in this prospectus supplement to our Yen revolving credit facility mean our operating partnership’s ¥33,285,000,000 (approximately $300 million based on exchange rates at December 31, 2018) senior unsecured revolving credit facility.

“Turn-Key Flex^®,” “Powered Base Buildings^®,” “POD Architecture^®” and “Critical Facilities Management^®” are trademarks of our company. All other trademarks or trade names appearing in this prospectus supplement and the accompanying prospectus are the property of their respective owners.

You should rely only on the information contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus and any “free writing prospectus” we authorize to be delivered to you. We have not, and the underwriters have not, authorized any other person to provide you with different or additional information. If anyone provides you with different or additional information, you should not rely on it. We are not, and the underwriters are not, making an offer to sell or soliciting an offer to buy the series K preferred stock in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement and the accompanying prospectus, including the documents incorporated by reference herein and therein, and any authorized “free writing prospectus” is accurate only as of their respective dates. Our business, financial condition, results of operations and prospects may have changed since those dates. The descriptions set forth in this prospectus supplement replace and supplement, where inconsistent, the description of the general terms and provisions set forth in the accompanying prospectus.

The distribution of this prospectus supplement, the accompanying prospectus and any authorized “free writing prospectus” and the offering of the series K preferred stock in certain jurisdictions may be restricted by law. If you possess this prospectus supplement, the accompanying prospectus or any authorized “free writing

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prospectus”, you should find out about and observe these restrictions. This prospectus supplement, the accompanying prospectus and any authorized “free writing prospectus” are not an offer to sell the series K preferred stock and are not soliciting an offer to buy the series K preferred stock in any jurisdiction where the offer or sale is not permitted or where the person making the offer or sale is not qualified to do so or to any person to whom it is not permitted to make such offer or sale. See “Underwriting (Conflicts of Interest)” in this prospectus supplement.

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RISK FACTORS

In addition to other information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and any “free writing prospectus” we authorize to be delivered to you, you should carefully consider the risks described below and incorporated herein by reference to our Combined Annual Report on Form 10-K for the year ended December 31, 2018, and other subsequent filings of Digital Realty Trust, Inc. and Digital Realty Trust, L.P. under the Exchange Act in evaluating our company, our properties and our business before making a decision to invest in the series K preferred stock. These risks are not the only ones faced by us. Additional risks not presently known to us or that we currently deem immaterial could also materially and adversely affect our financial condition, results of operations, business and prospects. The trading price of the series K preferred stock could decline due to any of these risks, and you may lose all or part of your investment. This prospectus supplement, the accompanying prospectus and the documents incorporated herein and therein by reference also contain forward-looking statements that involve risks and uncertainties. Actual results could differ materially from those anticipated in these forward-looking statements as a result of certain factors, including the risks faced by us described below and elsewhere in this prospectus supplement, the accompanying prospectus and the documents incorporated herein and therein by reference. Please refer to the section below entitled “Forward-Looking Statements.”

Risks Related to this Offering

The series K preferred stock is a new issuance, with no stated maturity date, and does not have an established trading market, which may negatively affect its market value and your ability to transfer or sell your shares.

The shares of series K preferred stock are a new issue of securities with no established trading market. In addition, because the series K preferred stock has no stated maturity date, investors seeking liquidity will be limited to selling their shares in the secondary market. We intend to file an application to list the series K preferred stock on the NYSE under the symbol “DLR Pr K” but there can be no assurance that the NYSE will approve the series K preferred stock for listing. Even if the NYSE approves our application, however, an active trading market on the NYSE for the shares may not develop or, even if it develops, may not last, in which case the trading price of the shares could be adversely affected and your ability to transfer your shares of series K preferred stock will be limited.

We have been advised by the underwriters that they intend to make a market in the shares of the series K preferred stock prior to the commencement of trading on the NYSE, but they are not obligated to do so and may discontinue market-making at any time without notice.

The series K preferred stock will be rated below investment grade by two of the three rating agencies that currently cover our securities.

The series K preferred stock will not be rated investment grade by two of the three rating agencies that currently cover our securities and will be subject to a higher risk of price volatility than similar, higher-rated securities. Furthermore, increases in leverage of or deteriorating outlooks for an issuer, or volatile markets, could lead to significant deterioration in market prices of below-investment grade rated securities.

Ratings only reflect the views of the issuing rating agency or agencies and such ratings could at any time be revised downward or withdrawn entirely at the discretion of the issuing rating agency. Further, a rating is not a recommendation to purchase, sell or hold any particular security, including the series K preferred stock. In addition, ratings do not reflect market prices or suitability of a security for a particular investor and any rating of the series K preferred stock may not reflect all risks related to our company and our business, or the structure or market value of the series K preferred stock.

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We have significant outstanding indebtedness that involves significant debt service obligations, limits our operational and financial flexibility, exposes us to interest rate fluctuations and exposes us to the risk of default under our debt obligations.

As of December 31, 2018, our total indebtedness was approximately $11.5 billion. There are no limits on the amount of indebtedness we may incur other than limits contained in our existing debt financing agreements or future agreements that we may enter into or as may be set forth in any policy limiting the amount of indebtedness we may incur adopted by our board of directors. A substantial level of indebtedness could have adverse consequences for our business, financial condition and results of operations because it could, among other things:

Market interest rates and other factors may affect the value of the series K preferred stock and our common stock.

One of the factors that will influence the prices of the series K preferred stock and our common stock will be the dividend yield on the series K preferred stock and our common stock relative to market interest rates. An increase in market interest rates could cause the market prices of the series K preferred stock and our common stock to go down. The trading prices of the shares of the series K preferred stock and our common stock will also depend on many other factors, which may change from time to time, including:

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In addition, over the last several years, prices of equity securities in the U.S. trading markets have been experiencing extreme price fluctuations, and the market prices of our common stock and preferred stock have also fluctuated significantly during this period. As a result of these and other factors, investors who purchase the series K preferred stock in this offering may experience a decrease, which could be substantial and rapid, in the market price of the series K preferred stock, including decreases unrelated to our operating performance or prospects. Likewise, in the event that the series K preferred stock becomes convertible upon a Change of Control and is converted into our common stock, holders of our common stock issued on conversion may experience a similar decrease, which also could be substantial and rapid, in the market price of our common stock.

Our global revolving credit facility, term loan facility and Yen revolving credit facility may limit our ability to pay distributions to holders of the series K preferred stock.

Our operating partnership’s global revolving credit facility, term loan facility and Yen revolving credit facility prohibit us from making distributions to our stockholders, or redeeming or otherwise repurchasing shares of our capital stock, including the series K preferred stock, after the occurrence and during the continuance of an event of default, except in limited circumstances including as necessary to enable us to maintain our qualification as a REIT and to avoid the payment of income or excise tax. Consequently, after the occurrence and during the continuance of an event of default under our global revolving credit facility, term loan facility or Yen revolving credit facility, we may not be able to pay all or a portion of the dividends payable to the holders or make redemptions or repurchases of the series K preferred stock.

In addition, in the event of a default under our global revolving credit facility, term loan facility or Yen revolving credit facility, we would be unable to borrow under such facilities and any amounts we have borrowed thereunder could become immediately due and payable. The agreements governing our future debt instruments may also include restrictions on our ability to pay dividends to holders or make redemptions or repurchases of the series K preferred stock.

Shares of the series K preferred stock are subordinated to existing and future debt and your interests could be diluted by the issuance of additional preferred stock, including additional shares of the series K preferred stock, and by other transactions.

Payment of accrued dividends on the series K preferred stock will be subordinated to all of our existing and future debt and will be structurally subordinated to the obligations of our subsidiaries. In addition, we may issue additional shares of series K preferred stock or shares of another class or series of preferred stock ranking on parity with (or, upon the affirmative vote or consent of the holders of at least two-thirds of the outstanding shares of series K preferred stock together with each other class or series of preferred stock ranking on parity with the series K preferred stock with respect to the payment of dividends and the distribution of assets upon liquidation, dissolution or winding up and upon which like voting rights have been conferred and are exercisable, senior to) the series K preferred stock with respect to the payment of dividends and the distribution of assets upon liquidation, dissolution or winding up. Other than the conversion right afforded to holders of series K preferred stock upon the occurrence of a Change of Control as described under “Description of the Series K Preferred Stock—Conversion Rights” and other than the limited voting rights as described under “Description of the Series K Preferred Stock—Limited Voting Rights” below, none of the provisions relating to the series K preferred stock relate to or limit our indebtedness or afford the holders of the series K preferred stock protection in the event of a highly leveraged or other transaction, including a merger or the sale, lease or conveyance of all or substantially all our assets or business, that might adversely affect the holders of the series K preferred stock. These factors may affect the trading price of the series K preferred stock.

As a holder of series K preferred stock you have extremely limited voting rights.

Your voting rights as a holder of series K preferred stock will be limited. Shares of our common stock are currently the only class of our securities carrying full voting rights. Voting rights for holders of series K preferred

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stock exist primarily with respect to voting on amendments to our charter, including our articles supplementary (in some cases, voting together with the holders of other series of preferred stock upon which like voting rights have been conferred and are exercisable, including the series C preferred stock, the series G preferred stock, the series H preferred stock, the series I preferred stock and the series J preferred stock), that materially and adversely affect the rights of the series K preferred stock or create additional classes or series of preferred stock that are senior to the series K preferred stock and the ability to elect (voting separately as a class together with the holders of all other classes or series of preferred stock upon which like voting rights have been conferred and are exercisable, including the series C preferred stock, the series G preferred stock, the series H preferred stock, the series I preferred stock and the series J preferred stock) two additional directors to our board of directors in the event that six quarterly dividends (whether or not consecutive) payable on the series K preferred stock are in arrears. See “Description of the Series K Preferred Stock—Limited Voting Rights.”

The Change of Control conversion feature may not adequately compensate you and may make it more difficult for a party to take over our company or discourage a party from taking over our company.

Upon the occurrence of a Change of Control, holders of the series K preferred stock will have the right (unless, prior to the Change of Control Conversion Date, we have provided or provide notice of our election to redeem the series K preferred stock) to convert some or all of their series K preferred stock into shares of our common stock (or equivalent value of alternative consideration). See “Description of the Series K Preferred Stock—Conversion Rights.” Upon such a conversion, the holders will be limited to a maximum number of shares of our common stock equal to the Share Cap multiplied by the number of shares of series K preferred stock converted. If the Common Stock Price is less than $57.325 (which is approximately 50% of the per-share closing sale price of our common stock reported on the NYSE on March 1, 2019), subject to adjustment, the holders will receive a maximum of 0.43611 shares of our common stock per share of series K preferred stock, which may result in a holder receiving a value that is less than the liquidation preference of the series K preferred stock. In addition, the Change of Control conversion feature of the series K preferred stock may have the effect of discouraging a third party from making an acquisition proposal for our company or of delaying, deferring or preventing certain change of control transactions of our company under circumstances that otherwise could provide the holders of our common stock and series K preferred stock with the opportunity to realize a premium over the then-current market price or that stockholders may otherwise believe is in their best interests.

The articles supplementary establishing the terms of the series K preferred stock will contain restrictions upon ownership and transfer of the series K preferred stock.

The articles supplementary establishing the terms of the series K preferred stock will contain restrictions on ownership and transfer of the series K preferred stock intended to assist us in maintaining our status as a REIT for United States federal income tax purposes. For example, the terms of the series K preferred stock will restrict any person from acquiring actual or constructive ownership of more than 9.8% (by value or number of shares, whichever is more restrictive) of the outstanding shares of our series K preferred stock and 9.8% (by value) of our outstanding capital stock. See “Description of the Series K Preferred Stock—Restrictions on Ownership and Transfer” in this prospectus supplement. You should consider these ownership limitations prior to your purchase of the series K preferred stock. In addition, the articles supplementary will provide that, notwithstanding any other provision of the series K preferred stock, no holder of series K preferred stock will be entitled to convert such stock into our common stock to the extent that receipt of our common stock would cause the holder to exceed the ownership limitations contained in our charter, which may limit your ability to convert the series K preferred stock into our common stock upon a Change of Control. These ownership restrictions could also have anti-takeover effects and could reduce the possibility that a third party will attempt to acquire control of the company, which could adversely affect the market price of the series K preferred stock.

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If our common stock is delisted, your ability to transfer or sell your shares of the series K preferred stock may be limited and the market value of the series K preferred stock will be materially adversely affected.

Other than in connection with certain change of control transactions, the series K preferred stock does not contain provisions that protect you if our common stock is delisted. Since the series K preferred stock has no stated maturity date, you may be forced to hold your shares of the series K preferred stock and receive stated dividends on the stock when, as and if authorized by our board of directors and declared by us with no assurance as to ever receiving the liquidation preference. In addition, if our common stock is delisted, it is likely that the series K preferred stock will be delisted as well. Accordingly, if our common stock is delisted, your ability to transfer or sell your shares of the series K preferred stock may be limited and the market value of the series K preferred stock will be materially adversely affected.

Our ability to pay dividends is limited by the requirements of Maryland law.

Our ability to pay dividends on the series K preferred stock is limited by the laws of Maryland. Under applicable Maryland law, a Maryland corporation generally may not make a distribution if, after giving effect to the distribution, the corporation would not be able to pay its debts as the debts become due in the usual course of business, or the corporation’s total assets would be less than the sum of its total liabilities plus, unless the corporation’s charter provides otherwise, the amount that would be needed, if the corporation were dissolved at the time of the distribution, to satisfy the preferential rights upon dissolution of stockholders whose preferential rights are superior to those receiving the distribution. Accordingly, we generally may not make a distribution on the series K preferred stock if, after giving effect to the distribution, we would not be able to pay our debts as they become due in the usual course of business or our total assets would be less than the sum of our total liabilities plus, unless the terms of such class or series provide otherwise, the amount that would be needed to satisfy the preferential rights upon dissolution of the holders of shares of any class or series of preferred stock then outstanding, if any, with preferences senior to those of the series K preferred stock.

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FORWARD-LOOKING STATEMENTS

We make statements in this prospectus supplement, the accompanying prospectus and the documents incorporated herein and therein by reference that are forward-looking statements within the meaning of the federal securities laws. In particular, statements pertaining to our capital resources, portfolio performance, ability to lease vacant space and space under development, leverage policy and acquisition and capital expenditure plans, as well as our discussion of “Factors Which May Influence Future Results of Operations,” contain forward-looking statements. Likewise, all of our statements regarding anticipated market conditions, demographics and results of operations are forward-looking statements. You can identify forward-looking statements by the use of forward-looking terminology such as “believes,” “expects,” “may,” “will,” “should,” “seeks,” “approximately,” “intends,” “plans,” “pro forma,” “estimates” or “anticipates” or the negative of these words and phrases or similar words or phrases which are predictions of or indicate future events or trends and which do not relate solely to historical matters. You can also identify forward-looking statements by discussions of strategy, plans or intentions.

Forward-looking statements involve numerous risks and uncertainties and you should not rely on them as predictions of future events. Forward-looking statements depend on assumptions, data or methods which may be incorrect or imprecise and we may not be able to realize them. We do not guarantee that the transactions and events described will happen as described or that they will happen at all. The following factors, among others, could cause actual results and future events to differ materially from those set forth or contemplated in the forward-looking statements:

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While forward-looking statements reflect our good faith beliefs, they are not guarantees of future performance. We disclaim any obligation to publicly update or revise any forward-looking statement to reflect changes in underlying assumptions or factors, new information, data or methods, future events or other changes. The risks included here are not exhaustive, and additional factors could adversely affect our business and financial performance, including factors and risks included in other sections of this prospectus supplement, the accompanying prospectus or the documents incorporated by reference herein or therein. Those risks continue to be relevant to our performance and financial condition. Moreover, we operate in a very competitive and rapidly changing environment. New risk factors emerge from time to time and it is not possible for management to predict all such risk factors, nor can we assess the impact of all such risk factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. Given these risks and uncertainties, investors should not place undue reliance on forward-looking statements as a prediction of actual results. For a further discussion of these and other factors that could impact our future results, performance or transactions, see the section entitled “Risk Factors” in this prospectus supplement, in the accompanying prospectus and in our Combined Annual Report on Form 10-K for the year ended December 31, 2018, as may be updated by subsequent filings with the SEC that are incorporated by reference herein and therein.

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USE OF PROCEEDS

We expect that the net proceeds from this offering will be approximately $192.7 million (or approximately $221.8 million if the underwriters’ over-allotment option to purchase additional shares is exercised in full) after deducting the underwriting discounts and commissions and our estimated expenses of approximately $1.0 million.

We intend to use the net proceeds from this offering to repay borrowings outstanding under Digital Realty Trust, L.P.’s global revolving credit facility, acquire additional properties or businesses, fund development opportunities, and to provide for working capital and other general corporate purposes, including potentially for the repayment of other debt or the repurchase, redemption, or retirement of outstanding debt securities or preferred stock, or a combination of the foregoing.

Our global revolving credit facility provides for borrowings in Australian dollars, British pounds sterling, Canadian dollars, Euros, Hong Kong dollars, Japanese yen, Singapore dollars, and U.S. dollars, and includes the ability to add additional currencies in the future, subject to the receipt of lender commitments in such currencies and the satisfaction of other conditions. As of December 31, 2018, approximately $1.5 billion was drawn under the global revolving credit facility and $44.5 million of letters of credit were issued, leaving approximately $0.8 billion available for use. As of December 31, 2018, borrowings under the global revolving credit facility bore interest at an overall blended rate of 2.57% comprised of 3.37% (U.S. dollars), 1.61% (GBP), 0.90% (Euro), 3.14% (Hong Kong dollars), 0.90% (Japanese yen), 2.79% (Singapore dollars), 2.82% (Australian dollars) and 3.16% (Canadian dollars). The interest rates are based on 1-month LIBOR, 1-month EURIBOR, 1-month BBR, 1-month HIBOR, 1-month JPY LIBOR, 1-month SOR, and 1-month CDOR, respectively, plus a margin of 0.90%. We have used and intend to use borrowings under the global revolving credit facility to acquire additional properties, fund development opportunities and to provide for working capital and other corporate purposes, including potentially for the repurchase, redemption or retirement of outstanding debt or equity securities.

Affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are lenders, affiliates of Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are co-documentation agents, an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is a syndication agent, Merrill Lynch, Pierce, Fenner & Smith Incorporated is a joint lead arranger and joint book running manager, and an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is an issuing bank under our operating partnership’s global revolving credit facility. Therefore, such underwriters and/or affiliates of such underwriters may receive more than 5% of the net proceeds from this offering through the repayment of the borrowings under the global revolving credit facility.

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CAPITALIZATION

The following table sets forth Digital Realty Trust, Inc.’s capitalization as of December 31, 2018:

This information should be read in conjunction with, and is qualified in its entirety by, our consolidated financial statements and schedule and the notes to our financial statements included in our Combined Annual Report on Form 10-K for the year ended December 31, 2018.

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DESCRIPTION OF THE SERIES K PREFERRED STOCK

The following summary of the material terms and provisions of the series K preferred stock of Digital Realty Trust, Inc. does not purport to be complete and is qualified in its entirety by reference to our charter, including the articles supplementary setting forth the terms of the series K preferred stock and our bylaws, as amended, each of which is available from us and is or will be filed with the SEC. This description of the particular terms of the series K preferred stock supplements, and to the extent inconsistent therewith replaces, the description of the general terms and provisions of our preferred stock set forth in the accompanying prospectus.

General

Our board of directors and a duly authorized committee of our board of directors classified 8,000,000 shares of the company’s authorized but unissued preferred stock as, and approved articles supplementary setting forth the terms of, a series of the company’s preferred stock, designated as the 5.850% series K cumulative redeemable preferred stock. When issued in accordance with this prospectus supplement and the accompanying prospectus, the series K preferred stock will be validly issued, fully paid and nonassessable. Our board of directors may authorize the issuance and sale of additional shares of series K preferred stock from time to time.

In connection with this offering, we, in accordance with the terms of the partnership agreement of our operating partnership, will contribute or otherwise transfer the net proceeds of the sale of the series K preferred stock to our operating partnership, and our operating partnership will issue to us 5.850% series K cumulative redeemable preferred units, or series K preferred units. Our operating partnership will be required to make all required distributions on the series K preferred units after any distribution of cash or assets to the holders of preferred units ranking senior to the series K preferred units as to distributions and liquidations that we may issue and prior to any distribution of cash or assets to the holders of common partnership units or to the holders of any other equity interest of our operating partnership, except for any other series of preferred units ranking on a parity with the series K preferred units as to distributions and liquidation, including our operating partnership’s series C cumulative redeemable perpetual preferred units, series G cumulative redeemable preferred units, series H cumulative redeemable preferred units, series I cumulative redeemable preferred units and series J cumulative redeemable preferred units; provided however, that our operating partnership may make such distributions as are necessary to enable us to maintain our qualification as a REIT.

We intend to file an application to list the series K preferred stock on the NYSE under the symbol “DLR Pr K”. We will use commercially reasonable efforts to have the listing application for the series K preferred stock approved. If the application is approved, trading of the series K preferred stock on the NYSE is expected to commence within 30 days after the date of initial delivery of the series K preferred stock. See “Underwriting (Conflicts of Interest)” in this prospectus supplement.

Ranking

The series K preferred stock will rank, with respect to dividend rights and rights upon voluntary or involuntary liquidation, dissolution or winding up of our affairs:

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The term “capital stock” does not include convertible or exchangeable debt securities, which, prior to conversion or exchange, rank senior in right of payment to the series K preferred stock. The series K preferred stock will also rank junior in right of payment to our other existing and future debt obligations.

Dividends

Subject to the preferential rights of the holders of any class or series of our capital stock ranking senior to the series K preferred stock with respect to dividend rights, holders of shares of the series K preferred stock are entitled to receive, when, as and if authorized by our board of directors and declared by us out of funds legally available for the payment of dividends, cumulative cash dividends at the rate of 5.850% per annum of the $25.00 liquidation preference per share of the series K preferred stock (equivalent to the fixed annual amount of $1.4625 per share of the series K preferred stock).

Dividends on the series K preferred stock will accrue and be cumulative from and including the date of original issue and will be payable to holders quarterly in arrears on or about the last day of March, June, September and December of each year or, if such day is not a business day, on either the immediately preceding business day or next succeeding business day at our option, except that, if such business day is in the next succeeding year, such payment shall be made on the immediately preceding business day, in each case with the same force and effect as if made on such date. The term “business day” means each day, other than a Saturday or a Sunday, which is not a day on which banks in New York are required to close.

The amount of any dividend payable on the series K preferred stock for any partial dividend period will be prorated and computed on the basis of a 360-day year consisting of twelve 30-day months. A dividend period is the respective period commencing on and including the first day of January, April, July and October of each year and ending on and including the day preceding the first day of the next succeeding dividend period (other than the initial dividend period and the dividend period during which any shares of series K preferred stock shall be redeemed). Dividends will be payable to holders of record as they appear in our stock records at the close of business on the applicable record date, which shall be the date designated by our board of directors as the record date for the payment of dividends that is not more than 35 and not fewer than 10 days prior to the scheduled dividend payment date.

The first dividend on the series K preferred stock is scheduled to be paid on June 28, 2019 and will be a pro rata dividend from and including the original issue date to and including June 30, 2019 in the amount of $0.43875 per share.

Dividends on the series K preferred stock will accrue whether or not:

Except as described in the next two paragraphs, unless full cumulative dividends on the series K preferred stock for all past dividend periods shall have been or contemporaneously are declared and paid in cash or declared and a sum sufficient for the payment thereof in cash is set apart for payment, we will not:

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The foregoing sentence, however, will not prohibit:

When we do not pay dividends in full (and do not set apart a sum sufficient to pay them in full) on the series K preferred stock and the shares of any other class or series of capital stock ranking, as to dividends, on parity with the series K preferred stock, we will declare any dividends upon the series K preferred stock and each such other class or series of capital stock ranking, as to dividends, on parity with the series K preferred stock pro rata, so that the amount of dividends declared per share of series K preferred stock and such other class or series of capital stock will in all cases bear to each other the same ratio that accrued dividends per share on the series K preferred stock and such other class or series of capital stock (which will not include any accrual in respect of unpaid dividends on such other class or series of capital stock for prior dividend periods if such other class or series of capital stock does not have a cumulative dividend) bear to each other. No interest, or sum of money in lieu of interest, will be payable in respect of any dividend payment or payments on the series K preferred stock which may be in arrears.

Holders of shares of series K preferred stock are not entitled to any dividend, whether payable in cash, property or shares of capital stock, in excess of full cumulative dividends on the series K preferred stock as described above. Any dividend payment made on the series K preferred stock will first be credited against the earliest accrued but unpaid dividends due with respect to those shares which remain payable. Accrued but unpaid dividends on the series K preferred stock will accumulate as of the dividend payment date on which they first become payable.

We do not intend to declare dividends on the series K preferred stock, or pay or set apart for payment dividends on the series K preferred stock, if the terms of any of our agreements, including any agreements relating to our indebtedness, prohibit such a declaration, payment or setting apart for payment or provide that such declaration, payment or setting apart for payment would constitute a breach of or default under such an agreement. Likewise, no dividends will be authorized by our board of directors and declared by us or paid or set apart for payment if such authorization, declaration or payment is restricted or prohibited by law.

Our Yen revolving credit facility, global revolving credit facility and term loan facility prohibit us from making distributions to our stockholders, or redeeming or otherwise repurchasing shares of our capital stock, including the series K preferred stock, after the occurrence and during the continuance of an event of default, except in limited circumstances including as necessary to enable us to maintain our qualification as a REIT and to avoid the payment of income or excise tax. Consequently, after the occurrence and during the continuance of an event of default under our global revolving credit facility or term loan facility, we may not be able to pay all or a portion of the dividends payable to the holders of the series K preferred stock or redeem all or a portion of the series K preferred stock. In addition, in the event of a default under our global revolving credit facility or term loan facility, we would be unable to borrow under such facilities and any amounts we have borrowed thereunder could become immediately due and payable. The agreements governing our future debt instruments may also include restrictions on our ability to pay dividends to holders or make redemptions of the series K preferred stock.

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Liquidation Preference

Upon any voluntary or involuntary liquidation, dissolution or winding up of our affairs, before any distribution or payment shall be made to holders of shares of our common stock or any other class or series of capital stock ranking, as to rights upon any voluntary or involuntary liquidation, dissolution or winding up of our affairs, junior to the series K preferred stock, holders of shares of series K preferred stock will be entitled to be paid out of our assets legally available for distribution to our stockholders, after payment of or provision for our debts and other liabilities, a liquidation preference of $25.00 per share of series K preferred stock, plus an amount equal to any accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the date of payment. If, upon our voluntary or involuntary liquidation, dissolution or winding up, our available assets are insufficient to pay the full amount of the liquidating distributions on all outstanding shares of series K preferred stock and the corresponding amounts payable on all shares of each other class or series of capital stock ranking, as to rights upon liquidation, dissolution or winding up, on parity with the series K preferred stock in the distribution of assets, then holders of shares of series K preferred stock and each such other class or series of capital stock ranking, as to rights upon any voluntary or involuntary liquidation, dissolution or winding up, on parity with the series K preferred stock will share ratably in any distribution of assets in proportion to the full liquidating distributions to which they would otherwise be respectively entitled.

Holders of shares of series K preferred stock will be entitled to written notice of any distribution in connection with any voluntary or involuntary liquidation, dissolution or winding up of our affairs not less than 30 days and not more than 60 days prior to the distribution payment date. After payment of the full amount of the liquidating distributions to which they are entitled, holders of shares of series K preferred stock will have no right or claim to any of our remaining assets. Our consolidation or merger with or into any other corporation, trust or other entity, or the voluntary sale, lease, transfer or conveyance of all or substantially all of our property or business, will not be deemed to constitute a liquidation, dissolution or winding up of our affairs.

In determining whether a distribution (other than upon voluntary or involuntary liquidation), by dividend, redemption or other acquisition of shares of our capital stock or otherwise, is permitted under Maryland law, amounts that would be needed, if we were to be dissolved at the time of the distribution, to satisfy the preferential rights upon dissolution of holders of shares of series K preferred stock will not be added to our total liabilities.

Optional Redemption

Except with respect to the special optional redemption described below and in certain limited circumstances relating to our maintenance of our ability to qualify as a REIT as described in “—Restrictions on Ownership and Transfer,” we cannot redeem the series K preferred stock prior to March 13, 2024. On and after March 13, 2024, we may, at our option, upon not fewer than 30 and not more than 60 days’ written notice, redeem the series K preferred stock, in whole or in part, at any time or from time to time, for cash at a redemption price of $25.00 per share, plus all accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the date fixed for redemption, without interest, to the extent we have funds legally available for that purpose.

If fewer than all of the outstanding shares of the series K preferred stock are to be redeemed, we will select the shares of series K preferred stock to be redeemed pro rata (as nearly as may be practicable without creating fractional shares) or by lot as we determine. If such redemption is to be by lot and, as a result of such redemption, any holder of shares of series K preferred stock, other than a holder of series K preferred stock that has received an exemption from the ownership limit, would have actual or constructive ownership of more than 9.8% of the issued and outstanding shares of series K preferred stock by value or number of shares, whichever is more restrictive, or more than 9.8% in value of the aggregate outstanding shares of capital stock because such holder’s shares of series K preferred stock were not redeemed, or were only redeemed in part, then, except as otherwise provided in the charter, we will redeem the requisite number of shares of series K preferred stock of such holder such that no holder will own in excess of the 9.8% series K preferred stock ownership limit or the 9.8% capital stock ownership limit subsequent to such redemption. See “—Restrictions on Ownership and Transfer.” In order

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for their shares of series K preferred stock to be redeemed, holders must surrender their shares at the place, or in accordance with the book-entry procedures, designated in the notice of redemption. Holders will then be entitled to the redemption price and any accrued and unpaid dividends payable upon redemption following surrender of the shares as detailed below. If a notice of redemption has been given (in the case of a redemption of the series K preferred stock other than to preserve our status as a REIT), if the funds necessary for the redemption have been set aside by us in trust for the benefit of the holders of any shares of series K preferred stock called for redemption and if irrevocable instructions have been given to pay the redemption price and all accrued and unpaid dividends, then from and after the redemption date, dividends will cease to accrue on such shares of series K preferred stock and such shares of series K preferred stock will no longer be deemed outstanding. At such time, all rights of the holders of such shares will terminate, except the right to receive the redemption price plus any accrued and unpaid dividends payable upon redemption, without interest. So long as no dividends are in arrears and subject to the provisions of applicable law, we may from time to time repurchase all or any part of the series K preferred stock, including the repurchase of shares of series K preferred stock in open-market transactions and individual purchases at such prices as we negotiate, in each case as duly authorized by our board of directors.

Unless full cumulative dividends on all shares of series K preferred stock have been or contemporaneously are authorized, declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for all past dividend periods, no shares of series K preferred stock will be redeemed unless all outstanding shares of series K preferred stock are simultaneously redeemed and we will not purchase or otherwise acquire directly or indirectly any shares of series K preferred stock or any class or series of our capital stock ranking, as to dividends or upon liquidation, dissolution or winding up, on parity with or junior to the series K preferred stock (except by exchange for our capital stock ranking junior to the series K preferred stock as to dividends and upon liquidation); provided, however, that whether or not the requirements set forth above have been met, we may purchase shares of series K preferred stock, preferred stock ranking on parity with the series K preferred stock as to payment of dividends and upon liquidation, dissolution or winding up or capital stock or equity securities ranking junior to the series K preferred stock pursuant to our charter to the extent necessary to ensure that we continue to meet the requirements for qualification as a REIT for federal income tax purposes, and may purchase or acquire shares of series K preferred stock pursuant to a purchase or exchange offer made on the same terms to holders of all outstanding shares of series K preferred stock. See “—Restrictions on Ownership and Transfer” below.

We will mail notice of redemption, postage prepaid, not less than 30 nor more than 60 days prior to the redemption date, addressed to the respective holders of record of the series K preferred stock to be redeemed at their respective addresses as they appear on our stock transfer records as maintained by the transfer agent named in “—Transfer Agent and Registrar.” No failure to give such notice or any defect therein or in the mailing thereof will affect the validity of the proceedings for the redemption of any shares of series K preferred stock except as to the holder to whom notice was defective or not given. In addition to any information required by law or by the applicable rules of any exchange upon which the series K preferred stock may be listed or admitted to trading, each notice will state:

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If fewer than all of the shares of series K preferred stock held by any holder are to be redeemed, the notice mailed to such holder will also specify the number of shares of series K preferred stock held by such holder to be redeemed.

We are not required to provide such notice in the event we redeem series K preferred stock in order to maintain our status as a REIT.

If a redemption date falls after a dividend record date and on or prior to the corresponding dividend payment date, each holder of shares of the series K preferred stock at the close of business of such dividend record date will be entitled to the dividend payable on such shares on the corresponding dividend payment date notwithstanding the redemption of such shares on or prior to such dividend payment date and each holder of shares of series K preferred stock that surrenders such shares on such redemption date will be entitled to the dividends accruing after the end of the applicable dividend period, up to but excluding the redemption date. Except as described above, we will make no payment or allowance for unpaid dividends, whether or not in arrears, on series K preferred stock for which a notice of redemption has been given.

All shares of series K preferred stock that we redeem or repurchase will be retired and restored to the status of authorized but unissued shares of preferred stock, without designation as to series or class.

Our Yen revolving credit facility, global revolving credit facility and term loan facility prohibit us from redeeming or otherwise repurchasing any shares of our capital stock, including the series K preferred stock, after the occurrence and during the continuance of an event of default, except in limited circumstances.

Special Optional Redemption

Upon the occurrence of a Change of Control (as defined below), we may, at our option, redeem the series K preferred stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date, we have provided or provide notice of redemption with respect to the series K preferred stock (whether pursuant to our optional redemption right or our special optional redemption right), the holders of series K preferred stock will not have the conversion right described below under “—Conversion Rights.”

We will mail to you, if you are a record holder of the series K preferred stock, a notice of redemption no fewer than 30 days nor more than 60 days before the redemption date. We will send the notice to your address shown on our share transfer books. A failure to give notice of redemption or any defect in the notice or in its mailing will not affect the validity of the redemption of any series K preferred stock except as to the holder to whom notice was defective. Each notice will state the following:

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If we redeem fewer than all of the outstanding shares of series K preferred stock, the notice of redemption mailed to each stockholder will also specify the number of shares of series K preferred stock that we will redeem from each stockholder. In this case, we will determine the number of shares of series K preferred stock to be redeemed as described above in “—Optional Redemption.”

If we have given a notice of redemption and have set aside sufficient funds for the redemption in trust for the benefit of the holders of the series K preferred stock called for redemption, then from and after the redemption date, those shares of series K preferred stock will be treated as no longer being outstanding, no further dividends will accrue and all other rights of the holders of those shares of series K preferred stock will terminate. The holders of those shares of series K preferred stock will retain their right to receive the redemption price for their shares and any accrued and unpaid dividends through, but not including, the redemption date, without interest.

The holders of series K preferred stock at the close of business on a dividend record date will be entitled to receive the dividend payable with respect to the series K preferred stock on the corresponding payment date notwithstanding the redemption of the series K preferred stock between such record date and the corresponding payment date or our default in the payment of the dividend due. Except as provided above, we will make no payment or allowance for unpaid dividends, whether or not in arrears, on series K preferred stock to be redeemed.

A “Change of Control” is when, after the original issuance of the series K preferred stock, the following have occurred and are continuing:

Conversion Rights

Upon the occurrence of a Change of Control, each holder of series K preferred stock will have the right, unless, prior to the Change of Control Conversion Date, we have provided or provide notice of our election to

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redeem the series K preferred stock as described under “—Optional Redemption” or “—Special Optional Redemption,” to convert some or all of the series K preferred stock held by such holder (the “Change of Control Conversion Right”) on the Change of Control Conversion Date into a number of shares of our common stock per share of series K preferred stock (the “Common Stock Conversion Consideration”), which is equal to the lesser of:

The Share Cap is subject to pro rata adjustments for any share splits (including those effected pursuant to a distribution of our common stock), subdivisions or combinations (in each case, a “Share Split”) with respect to our common stock as follows: the adjusted Share Cap as the result of a Share Split will be the number of shares of our common stock that is equivalent to the product obtained by multiplying (i) the Share Cap in effect immediately prior to such Share Split by (ii) a fraction, the numerator of which is the number of shares of our common stock outstanding after giving effect to such Share Split and the denominator of which is the number of shares of our common stock outstanding immediately prior to such Share Split.

For the avoidance of doubt, subject to the immediately succeeding sentence, the aggregate number of shares of our common stock (or equivalent Alternative Conversion Consideration (as defined below), as applicable) issuable in connection with the exercise of the Change of Control Conversion Right will not exceed 3,488,880 shares of common stock (or equivalent Alternative Conversion Consideration, as applicable), subject to increase to the extent the underwriters’ over-allotment option to purchase additional shares of series K preferred stock is exercised, not to exceed 4,012,212 shares of common stock in total (or equivalent Alternative Conversion Consideration, as applicable) (the “Exchange Cap”). The Exchange Cap is subject to pro rata adjustments for any Share Splits on the same basis as the corresponding adjustments to the Share Cap and is subject to increase in the event that additional shares of series K preferred stock are issued in the future.

In the case of a Change of Control pursuant to which our common stock will be converted into cash, securities or other property or assets (including any combination thereof) (the “Alternative Form Consideration”), a holder of series K preferred stock will receive upon conversion of such series K preferred stock the kind and amount of Alternative Form Consideration which such holder would have owned or been entitled to receive upon the Change of Control had such holder held a number of shares of our common stock equal to the Common Stock Conversion Consideration immediately prior to the effective time of the Change of Control (the “Alternative Conversion Consideration,” and the Common Stock Conversion Consideration or the Alternative Conversion Consideration, as may be applicable to a Change of Control, is referred to as the “Conversion Consideration”).

If the holders of our common stock have the opportunity to elect the form of consideration to be received in the Change of Control, the Conversion Consideration will be deemed to be the kind and amount of consideration actually received by holders of a majority of our common stock that voted for such an election (if electing between two types of consideration) or holders of a plurality of our common stock that voted for such an election (if electing between more than two types of consideration), as the case may be, and will be subject to any limitations to which all holders of our common stock are subject, including, without limitation, pro rata reductions applicable to any portion of the consideration payable in the Change of Control.

We will not issue fractional shares of common stock upon the conversion of the series K preferred stock. Instead, we will pay the cash value of such fractional shares.

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Within 15 days following the occurrence of a Change of Control, we will provide to holders of series K preferred stock a notice of occurrence of the Change of Control that describes the resulting Change of Control Conversion Right. This notice will state the following:

We will issue a press release for publication on the Dow Jones & Company, Inc., Business Wire, PR Newswire or Bloomberg Business News (or, if these organizations are not in existence at the time of issuance of the press release, such other news or press organization as is reasonably calculated to broadly disseminate the relevant information to the public), or post a notice on our website, in any event prior to the opening of business on the first business day following any date on which we provide the notice described above to the holders of series K preferred stock.

To exercise the Change of Control Conversion Right, the holders of series K preferred stock will be required to deliver, on or before the close of business on the Change of Control Conversion Date, the certificates (if any) representing series K preferred stock to be converted, duly endorsed for transfer, together with a written conversion notice completed, to our transfer agent. The conversion notice must state:

The “Change of Control Conversion Date” is the date the series K preferred stock is to be converted, which will be a business day that is no fewer than 20 days nor more than 35 days after the date on which we provide the notice described above to the holders of series K preferred stock.

The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of our common stock is solely cash, the amount of cash consideration per share of our common stock or (ii) if the consideration to be received in the Change of Control by holders of our common stock is other than solely cash (x) the average of the closing sale prices per share of our common stock (or, if no closing sale price is reported, the average of the closing bid and ask prices or, if more than one in either case, the average of the average closing bid and the average closing ask prices) for the ten consecutive trading days immediately

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preceding, but not including, the effective date of the Change of Control as reported on the principal U.S. securities exchange on which our common stock is then traded, or (y) the average of the last quoted bid prices for our common stock in the over-the-counter market as reported by Pink Sheets LLC or similar organization for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control, if our common stock is not then listed for trading on a U.S. securities exchange.

Holders of series K preferred stock may withdraw any notice of exercise of a Change of Control Conversion Right (in whole or in part) by a written notice of withdrawal delivered to our transfer agent prior to the close of business on the business day prior to the Change of Control Conversion Date. The notice of withdrawal must state:

Notwithstanding the foregoing, if the series K preferred stock is held in global form, the conversion notice and/or the notice of withdrawal, as applicable, must comply with applicable procedures of The Depository Trust Company, or DTC.

The series K preferred stock as to which the Change of Control Conversion Right has been properly exercised and for which the conversion notice has not been properly withdrawn will be converted into the applicable Conversion Consideration in accordance with the Change of Control Conversion Right on the Change of Control Conversion Date, unless prior to the Change of Control Conversion Date we have provided or provide notice of our election to redeem such series K preferred stock, whether pursuant to our optional redemption right or our special optional redemption right. If we elect to redeem series K preferred stock that would otherwise be converted into the applicable Conversion Consideration on a Change of Control Conversion Date, such series K preferred stock will not be so converted and the holders of such shares will be entitled to receive on the applicable redemption date $25.00 per share, plus any accrued and unpaid dividends thereon to, but not including, the redemption date, in accordance with our optional redemption right or special optional redemption right. See “—Redemption” and “—Special Optional Redemption” above.

We will deliver amounts owing upon conversion no later than the third business day following the Change of Control Conversion Date.

In connection with the exercise of any Change of Control Conversion Right, we will comply with all federal and state securities laws and stock exchange rules in connection with any conversion of series K preferred stock into shares of our common stock. Notwithstanding any other provision of the series K preferred stock, no holder of series K preferred stock will be entitled to convert such series K preferred stock into shares of our common stock to the extent that receipt of such common stock would cause such holder (or any other person) to exceed the share ownership limits contained in our charter, including the articles supplementary setting forth the terms of the series K preferred stock, unless we provide an exemption from this limitation for such holder. See “—Restrictions on Ownership and Transfer” below.

The Change of Control conversion feature may make it more difficult for a party to take over our company or discourage a party from taking over our company. See “Risk Factors—Risks Related to This Offering—The Change of Control conversion feature may not adequately compensate you and may make it more difficult for a party to take over our company or discourage a party from taking over our company.”

Except as provided above in connection with a Change of Control, the series K preferred stock is not convertible into or exchangeable for any other securities or property.

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No Maturity, Sinking Fund or Mandatory Redemption

The series K preferred stock has no maturity date and we are not required to redeem the series K preferred stock at any time. Accordingly, the series K preferred stock will remain outstanding indefinitely, unless we decide, at our option, to exercise our redemption right or, under circumstances where the holders of the series K preferred stock have a conversion right, such holders convert the series K preferred stock into our common stock. The series K preferred stock is not subject to any sinking fund.

Limited Voting Rights

Holders of shares of the series K preferred stock generally do not have any voting rights, except as set forth below.

If dividends on the series K preferred stock are in arrears for six or more quarterly periods, whether or not consecutive (which we refer to as a preferred dividend default), holders of shares of the series K preferred stock (voting separately as a class together with the holders of all other classes or series of preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote for the election of two additional directors to serve on our board of directors (which we refer to as preferred stock directors), until all unpaid dividends for past dividend periods with respect to the series K preferred stock and any other class or series of preferred stock upon which like voting rights have been conferred and are exercisable have been paid. In such a case, the number of directors serving on our board of directors will be increased by two. The preferred stock directors will be elected by a plurality of the votes cast in the election for a one-year term and each preferred stock director will serve until his successor is duly elected and qualifies or until the director’s right to hold the office terminates, whichever occurs earlier. The election will take place at:

If and when all accumulated dividends on the series K preferred stock and all other classes or series of preferred stock upon which like voting rights have been conferred and are exercisable shall have been paid in full, holders of shares of series K preferred stock shall be divested of the voting rights set forth above (subject to re-vesting in the event of each and every preferred dividend default) and the term and office of such preferred stock directors so elected will terminate and the entire board of directors will be reduced accordingly.

Any preferred stock director elected by holders of shares of series K preferred stock and other holders of preferred stock upon which like voting rights have been conferred and are exercisable may be removed at any time with or without cause by the vote of, and may not be removed otherwise than by the vote of, the holders of record of a majority of the outstanding shares of series K preferred stock and other parity preferred stock entitled to vote thereon when they have the voting rights described above (voting as a single class). So long as a preferred dividend default continues, any vacancy in the office of a preferred stock director may be filled by written consent of the preferred stock director remaining in office, or if none remains in office, by a vote of the holders of record of a majority of the outstanding shares of series K preferred stock when they have the voting rights described above (voting as a single class with all other classes or series of preferred stock upon which like voting rights have been conferred and are exercisable). The preferred stock directors shall each be entitled to one vote on any matter.

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In addition, so long as any shares of series K preferred stock remain outstanding, we will not, without the consent or the affirmative vote of the holders of at least two-thirds of the outstanding shares of series K preferred stock together with each other class or series of preferred stock ranking on parity with series K preferred stock with respect to the payment of dividends and the distribution of assets upon our liquidation, dissolution or winding up and upon which like voting rights have been conferred and are exercisable (voting together as a single class):

except that with respect to the occurrence of any of the events described in the second bullet point immediately above, so long as the series K preferred stock remains outstanding with the terms of the series K preferred stock materially unchanged, taking into account that, upon the occurrence of an event described in the second bullet point above, the company may not be the surviving entity, the occurrence of such event will not be deemed to materially and adversely affect the rights, preferences, privileges or voting power of the series K preferred stock, and in such case such holders shall not have any voting rights with respect to the events described in the second bullet point immediately above. Furthermore, if holders of shares of the series K preferred stock receive the greater of the full trading price of the series K preferred stock on the date of an event described in the second bullet point immediately above or the $25.00 per share liquidation preference pursuant to the occurrence of any of the events described in the second bullet point immediately above, then such holders shall not have any voting rights with respect to the events described in the second bullet point immediately above. If any event described in the second bullet point above would materially and adversely affect the rights, preferences, privileges or voting powers of the series K preferred stock disproportionately relative to other classes or series of preferred stock ranking on parity with the series K preferred stock with respect to the payment of dividends and the distribution of assets upon our liquidation, dissolution or winding up, the affirmative vote of the holders of at least two-thirds of the outstanding shares of the series K preferred stock, voting separately as a class, will also be required.

Holders of shares of series K preferred stock will not be entitled to vote with respect to any increase in the total number of authorized shares of our common stock or preferred stock, any increase in the number of authorized shares of series K preferred stock or the creation or issuance of any other class or series of capital stock, or any increase in the number of authorized shares of any other class or series of capital stock, in each case ranking on parity with or junior to the series K preferred stock with respect to the payment of dividends and the distribution of assets upon liquidation, dissolution or winding up.

Holders of shares of series K preferred stock will not have any voting rights with respect to, and the consent of the holders of shares of series K preferred stock is not required for, the taking of any corporate action, including any merger or consolidation involving us or a sale of all or substantially all of our assets, regardless of the effect that such merger, consolidation or sale may have upon the powers, preferences, voting power or other rights or privileges of the series K preferred stock, except as set forth above.

In addition, the voting provisions above will not apply if, at or prior to the time when the act with respect to which the vote would otherwise be required would occur, we have redeemed or called for redemption upon proper procedures all outstanding shares of series K preferred stock.

In any matter in which series K preferred stock may vote (as expressly provided in the articles supplementary setting forth the terms of the series K preferred stock), each share of series K preferred stock shall

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be entitled to one vote per $25.00 of liquidation preference. As a result, each share of series K preferred stock will be entitled to one vote.

Restrictions on Ownership and Transfer

In order for us to qualify as a REIT under the Code, our stock must be beneficially owned by 100 or more persons during at least 335 days of a taxable year of 12 months (other than the first year for which an election to be a REIT has been made) or during a proportionate part of a shorter taxable year. Also, not more than 50% of the value of the outstanding shares of our stock may be owned, directly or indirectly, by five or fewer individuals (as defined in the Code to include certain entities such as private foundations) during the last half of a taxable year (other than the first year for which an election to be a REIT has been made).

Our charter contains restrictions on the ownership and transfer of shares of our capital stock which are intended to assist us in complying with these requirements and continuing to qualify as a REIT. Our charter provides that, subject to certain exceptions, no person or entity may beneficially own, or be deemed to own by virtue of the applicable constructive ownership provisions of the Code, subject to limited exceptions, more than 9.8% (by value or by number of shares, whichever is more restrictive) of the outstanding shares of our series K preferred stock or more than 9.8% (by value) of our outstanding capital stock. For a further description of restrictions on ownership and transfer of all series and classes of shares of our capital stock, see “Restrictions on Ownership and Transfer” in the accompanying prospectus.

Transfer Agent

The transfer agent and registrar for the series K preferred stock is American Stock Transfer & Trust Company, LLC.

Book-Entry Procedures

The series K preferred stock will only be issued in the form of global securities held in book-entry form. DTC or its nominee will be the sole registered holder of the series K preferred stock. Owners of beneficial interests in the series K preferred stock represented by the global securities will hold their interests pursuant to the procedures and practices of DTC. As a result, beneficial interests in any such securities will be shown on, and transfers will be effected only through, records maintained by DTC and its direct and indirect participants and any such interest may not be exchanged for certificated securities, except in limited circumstances. Owners of beneficial interests must exercise any rights in respect of other interests, including any right to convert or require repurchase of their interests in the series K preferred stock, in accordance with the procedures and practices of DTC. Beneficial owners will not be holders and will not be entitled to any rights provided to the holders of the series K preferred stock under the global securities or the articles supplementary. We and any of our agents may treat DTC as the sole holder and registered owner of the global securities.

DTC has advised us as follows: DTC is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Uniformed Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Exchange Act. DTC facilitates the settlement of transactions amongst participants through electronic computerized book-entry changes in participants’ accounts, eliminating the need for physical movement of securities certificates. DTC’s participants include securities brokers and dealers, including the underwriters, banks, trust companies, clearing corporations and other organizations, some of whom and/or their representatives own DTC. Access to DTC’s book-entry system is also available to others, such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a participant, either directly or indirectly.

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The series K preferred stock, represented by one or more global securities, will be exchangeable for certificated securities with the same terms only if:

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SUPPLEMENTAL UNITED STATES FEDERAL INCOME TAX CONSIDERATIONS

For a discussion of certain material United States federal income tax consequences regarding our company and holders of our series K preferred stock, please see Exhibit 99.1 to our Current Report on Form 8-K filed with the SEC on January 4, 2019 (the “January 2019 Form 8-K”), which was filed pursuant to Item 8.01 of Form 8-K. The January 2019 Form 8-K (including Exhibit 99.1 thereto) is incorporated by reference into this prospectus supplement and the accompanying prospectus and supersedes and replaces, in its entirety, the discussion under the heading “United States Federal Income Tax Considerations” in the accompanying prospectus and in our registration statement on Form S-3 (File Nos. 333-220576 and 333-220576-01) filed with the SEC on September 22, 2017. Prospective investors in our series K preferred stock should consult their tax advisors regarding the United States federal income and other tax considerations to them of the acquisition, ownership and disposition of our series K preferred stock offered by this prospectus supplement.

The following discussion should follow the discussion under the heading “United States Federal Income Tax Considerations—Material U.S. Federal Income Tax Consequences to Holders of Our Capital Stock and the Operating Partnership’s Debt Securities—Taxation of Taxable U.S. Holders of Our Capital Stock—Redemption or Repurchase by Us” in the January 2019 Form 8-K.

Conversion of Series K Preferred Stock. Upon the occurrence of a Change of Control, each holder of series K preferred stock will have the right (unless, prior to the Change of Control Conversion Date, we have provided or provide notice of our election to redeem the series K preferred stock) to convert some or all of such holder’s series K preferred stock into shares of our common stock or the Alternative Conversion Consideration—i.e., an amount of cash, securities or other property or assets that such holder would have received upon the Change of Control had such holder converted the holder’s series K preferred stock into shares of our common stock immediately prior to the effective time of the Change of Control (see “Description of the Series K Preferred Stock—Conversion Rights” in this prospectus supplement). Except as provided below, a U.S. holder generally will not recognize gain or loss upon the conversion of series K preferred stock into shares of our common stock. A U.S. holder’s tax basis and holding period in the shares of common stock received upon conversion generally will be the same as those of the converted series K preferred stock (but the tax basis will be reduced by the portion of the adjusted tax basis allocated to any fractional share of common stock exchanged for cash).

Cash received upon conversion in lieu of a fractional share of common stock generally will be treated as a payment in a taxable exchange for such fractional share of common stock, and gain or loss will be recognized on the receipt of cash in an amount equal to the difference between the amount of cash received and the adjusted tax basis allocable to the fractional common share deemed exchanged. This gain or loss will be long-term capital gain or loss if the holder has held the series K preferred stock for more than one year. Any common stock received in exchange for accrued and unpaid dividends generally will be treated as a distribution by us, and subject to tax treatment as described in “—Material U.S. Federal Income Tax Consequences to Holders of Our Capital Stock and the Operating Partnership’s Debt Securities—Taxation of Taxable U.S. Holders of Our Capital Stock—Distributions Generally.”

In addition, if a holder receives the Alternative Conversion Consideration (in lieu of shares of our common stock) in connection with the conversion of the stockholder’s shares of series K preferred stock, the tax treatment of the receipt of any such other consideration will depend on the nature of the consideration and the structure of the transaction that gives rise to the Change of Control, and it may be a taxable exchange. U.S. holders converting their shares of series K preferred stock should consult their tax advisors regarding the U.S. federal income tax consequences of any such conversion and of the ownership and disposition of the consideration received upon any such conversion.

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The following discussion should follow the discussion under the heading “United States Federal Income Tax Considerations—Material U.S. Federal Income Tax Consequences to Holders of Our Capital Stock and the Operating Partnership’s Debt Securities—Taxation of Non-U.S. Holders of Our Capital Stock—Redemption or Repurchase by Us” in the January 2019 Form 8-K.

Conversion of Series K Preferred Stock. See “—Material U.S. Federal Income Tax Consequences to Holders of Our Capital Stock and the Operating Partnership’s Debt Securities—Taxation of Taxable U.S. Holders of Our Capital Stock—Conversion of Series K Preferred Stock” above for a discussion of certain U.S. federal income tax consequences to a holder of series K preferred stock upon a conversion of such holder’s series K preferred stock into shares of our common stock or the Alternative Conversion Consideration and any consideration received in respect of accrued and unpaid dividends or fractional shares. Whether or not a non-U.S. holder will recognize gain upon the conversion of series K preferred stock into shares of our common stock will depend on whether the shares of series K preferred stock, and the common stock into which they are converted, constitute USRPIs in the hands of the non-U.S. holder. Any common stock received in exchange for accrued and unpaid dividends generally will be treated as a distribution by us, and subject to tax treatment as described in “—Material U.S. Federal Income Tax Consequences to Holders of Our Capital Stock and the Operating Partnership’s Debt Securities—Taxation of Non-U.S. Holders of Our Capital Stock—Distributions Generally.” Non-U.S. holders converting their shares of series K preferred stock should consult their tax advisors regarding the U.S. federal income tax consequences of any such conversion and of the ownership and disposition of the consideration received upon any such conversion.

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UNDERWRITING (CONFLICTS OF INTEREST)

Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC, and Wells Fargo Securities, LLC are acting as representatives of the underwriters named below. Subject to the terms and conditions stated in the underwriting agreement, dated the date of this prospectus supplement, each underwriter named below has severally agreed to purchase, and we have agreed to sell to that underwriter, the number of shares of series K preferred stock set forth opposite the underwriter’s name.

The underwriting agreement provides that the obligations of the underwriters to purchase the shares included in the series K preferred stock offering are subject to approval of legal matters by counsel and to other specified conditions, which include: the representations and warranties made by us to the underwriters are true; there is no material adverse effect on our prospects, earnings, business or properties; and we deliver customary documents to the underwriters. The underwriters are obligated to purchase all of the shares, other than those covered by the option to purchase additional shares described below, if they purchase any of the shares. The underwriting agreement also provides that if an underwriter defaults, the purchase commitments of non-defaulting underwriters may be increased or this offering may be terminated.

The underwriters propose to offer some of the shares of the series K preferred stock directly to the public at the public offering price set forth on the cover page of this prospectus supplement and some of the shares of the series K preferred stock to dealers at the public offering price less a concession not to exceed $0.50 per share. The underwriters may allow, and dealers may re-allow, a concession not to exceed $0.45 per share on sales to other dealers. If all of the shares are not sold at the initial offering price, the representatives may change the public offering price and the other selling terms.

We have granted to the underwriters an option to purchase up to 1,200,000 additional shares of the series K preferred stock within 30 days from the date of this prospectus supplement solely to cover over-allotments at the public offering price less the underwriting discount. To the extent the option is exercised, each underwriter must purchase a number of additional shares of the series K preferred stock approximately proportionate to that underwriter’s initial purchase commitment.

Prior to the series K preferred stock offering, there has been no public market for the series K preferred stock. We intend to submit an application to list the series K preferred stock on the NYSE under the symbol “DLR Pr K”. We will use our commercially reasonable efforts to have the listing application for the series K preferred stock approved. If the application is approved, trading of the series K preferred stock is expected to commence within 30 days after the initial delivery of the series K preferred stock. The underwriters have advised us that they intend to make a market in the series K preferred stock prior to commencement of any trading on the NYSE, but they are not obligated to do so and may discontinue market making activities, if commenced, at any time without notice. No assurance can be given as to the liquidity of the trading market for the series K preferred stock.

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The following table shows the underwriting discounts and commissions that we will pay to the underwriters in connection with the series K preferred stock offering. These amounts are shown assuming both no exercise and full exercise of the underwriters’ option to purchase additional shares of series K preferred stock.

In connection with the offering, the underwriters may purchase and sell shares of series K preferred stock in the open market. Purchases and sales in the open market may include short sales, purchases to cover short positions, which may include purchases pursuant to the option to purchase additional shares, and transactions that have the effect of stabilizing purchases.

Purchases to cover short positions and transactions that have the effect of stabilizing purchases, as well as other purchases by the underwriters for their own accounts, may have the effect of preventing or retarding a decline in the market prices of the shares of series K preferred stock. They may also cause the price of the shares to be higher than the price that would otherwise exist in the open market in the absence of these transactions. The underwriters may conduct these transactions on the NYSE, in the over-the-counter market or otherwise. If the underwriters commence any of these transactions, they may discontinue them at any time.

For a period beginning on the date of this prospectus and through 30 days after the date of this prospectus, we and our operating partnership have agreed that we will not offer, sell, contract to sell, pledge or otherwise dispose of (or enter into any transaction which is designed to, or would be reasonably be expected to, result in the disposition of (whether by actual disposition or effective economic disposition due to cash settlement or otherwise)), directly or indirectly, including the filing (or participation in the filing) of a registration statement (including any amendments) under the Securities Act of 1933, as amended, or the

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Securities Act, with the SEC in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Exchange Act, with respect to, any of our preferred securities, or any securities convertible into, or exercisable, or exchangeable for, our preferred securities (in each case, other than shares of series K preferred stock), or publicly announce an intention to effect any such transaction, without the prior written consent of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC, and Wells Fargo Securities, LLC.

We estimate that our expenses related to this offering will be approximately $1.0 million excluding the underwriting discount. The underwriters have agreed to reimburse us for certain expenses in connection with this offering.

We and our operating partnership have agreed to indemnify the underwriters against liabilities under the Securities Act or contribute to payments that the underwriters may be required to make in that respect.

We expect that delivery of the series K preferred stock will be made against payment thereof on or about March 13, 2019 which will be the seventh business day following the pricing of the series K preferred stock (such settlement cycle being herein referred to as “T + 7”). Pursuant to Rule 15c6-1 under the Securities Exchange Act of 1934, trades in the secondary market generally are required to settle in two business days unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade series K preferred stock on the date of pricing or the next four business days will be required, by virtue of the fact that the series K preferred stock initially will settle T + 7, to specify an alternate settlement cycle at the time of any such trade to prevent a failed settlement. Purchasers of the series K preferred stock who wish to trade the series K preferred stock on the date of pricing of the series K preferred stock or the next four business days should consult their own advisor.

In the ordinary course of their business, the underwriters or their respective affiliates have also in the past performed, and may continue to perform, investment banking, broker dealer, financial advisory or other services for us, for which they have received, or may receive, customary fees and commissions. In addition, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investment and securities activities may involve securities and/or instruments of ours or our affiliates. Certain of the underwriters or their affiliates that have a lending relationship with us routinely hedge their credit exposure to us consistent with their customary risk management policies. Of the underwriters (or their affiliates) that have lending relationships with us, certain of them routinely hedge and others may hedge their credit exposure to us consistent with their customary risk management policies. Typically, these underwriters and/or their affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the series K preferred stock offered hereby. Any such credit default swaps or short positions could adversely affect future trading prices of the series K preferred stock offered hereby. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are lenders, affiliates of Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are co-documentation agents, an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is a syndication agent, Merrill Lynch, Pierce, Fenner & Smith Incorporated is a joint lead arranger and joint book running manager, and an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is an issuing bank under our operating partnership’s global revolving credit facility.

An affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is a syndication agent, affiliates of Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are co-documentation agents, Merrill Lynch,

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Pierce, Fenner & Smith Incorporated is a joint lead arranger and joint book running manager, and affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC and are lenders under our term loan facility.

Affiliates of Wells Fargo Securities, LLC are trustees under our 3.400% notes due 2020, our 3.625% notes due 2022, our 3.950% notes due 2022, our 4.750% notes due 2025, our 2.750% notes due 2023, our 3.700% notes due 2027, and our 4.450% notes due 2028.

Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are also sales agents under our sales agreement, pursuant to which we can issue and sell shares of our common stock having an aggregate offering price of up to $1.0 billion from time to time through them and the other sales agents named therein. In addition, certain of underwriters and their affiliates have in the past leased, currently lease and may in the future lease space from us.

Conflicts of Interest

Affiliates of Merrill Lynch, Pierce, Fenner & Smith Incorporated, Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are lenders, affiliates of Morgan Stanley & Co. LLC and Wells Fargo Securities, LLC are co-documentation agents, an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is a syndication agent, Merrill Lynch, Pierce, Fenner & Smith Incorporated is a joint lead arranger and joint book running manager, and an affiliate of Merrill Lynch, Pierce, Fenner & Smith Incorporated is an issuing bank under our operating partnership’s global revolving credit facility. Therefore, such underwriters and/or affiliates of such underwriters may receive more than 5% of the net proceeds from this offering through the repayment of the borrowings under the global revolving credit facility.

In connection with the offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means such as email.

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LEGAL MATTERS

Certain legal matters relating to this offering will be passed upon for us by Latham & Watkins LLP, Los Angeles, California, and for the underwriters by Goodwin Procter LLP, Boston, Massachusetts. Venable LLP, Baltimore, Maryland, will issue an opinion to us regarding certain matters of Maryland law, including the validity of the series K preferred stock.

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EXPERTS

The consolidated financial statements and financial statement schedule III of Digital Realty Trust, Inc. and subsidiaries as of December 31, 2018, 2017 and 2016 and for each of the years in the three-year period ended December 31, 2018 and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2018 have all been incorporated by reference in this prospectus supplement in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report on the effectiveness of internal control over financial reporting as of December 31, 2018, contains an explanatory paragraph that states the Company acquired Ascenty on December 20, 2018, and management excluded from its assessment of the effectiveness of the Company’s internal control over financial reporting as of December 31, 2018, Ascenty’s internal control over financial reporting associated with total assets of approximately $2 billion and total revenues of $3 million included in the consolidated financial statements of the Company as of and for the year-ended December 31, 2018. Our audit of internal control over financial reporting of the Company also excluded an evaluation of Ascenty’s internal control over financial reporting.

The consolidated financial statements and financial statement schedule III of Digital Realty Trust, L.P. and subsidiaries as of December 31, 2018, 2017 and 2016 and for each of the years in the three-year period ended December 31, 2018 have all been incorporated by reference in this prospectus supplement in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and special reports, proxy statements and other information with the SEC. The SEC also maintains a web site that contains reports, proxy and information statements, and other information regarding registrants that file electronically with the SEC at www.sec.gov. You can inspect reports and other information we file at the offices of the NYSE, 20 Broad Street, New York, New York 10005. In addition, we maintain a web site that contains information about us at www.digitalrealty.com. The information found on, or otherwise accessible through, our website is not incorporated into, and does not form a part of, this prospectus supplement, the accompanying prospectus or any other report or document we file with or furnish to the SEC.

We have filed with the SEC a registration statement on Form S-3 (File Nos. 333-220576 and 333-220576-01), of which this prospectus supplement and the accompanying prospectus are a part, including exhibits, schedules and amendments filed with, or incorporated by reference in, such registration statement, under the Securities Act. This prospectus supplement and the accompanying prospectus do not contain all of the information set forth in the registration statement and exhibits and schedules to the registration statement. For further information with respect to our company, reference is made to the registration statement, including the exhibits to the registration statement. Statements contained in this prospectus supplement and the accompanying prospectus as to the contents of any contract or other document referred to, or incorporated by reference, in this prospectus supplement and the accompanying prospectus are not necessarily complete and, where that contract or document is an exhibit to the registration statement, each statement is qualified in all respects by the exhibit to which the reference relates. Copies of the registration statement, including the exhibits and schedules to the registration statement, may be examined at the SEC’s public reference rooms at 100 F Street, N.E. Room 1580, Washington, DC 20549. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. Copies of all or a portion of the registration statement can be obtained from the public reference rooms of the SEC upon payment of prescribed fees. The registration statement is also available to you on the SEC’s web site, www.sec.gov. 

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” certain information we file with them which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus supplement. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus, and later information that we file with the SEC will automatically update and supersede this information. We incorporate by reference into this prospectus supplement and the accompanying prospectus the following documents (except for any document or portion thereof deemed to be “furnished” and not filed in accordance with SEC rules and regulations):

We will provide without charge to each person to whom a prospectus supplement is delivered, on written or oral request of that person, a copy of any or all of the documents we are incorporating by reference into this prospectus supplement, other than exhibits to those documents unless those exhibits are specifically incorporated by reference into those documents. A written request should be addressed to Investor Relations, Digital Realty Trust, Inc., Four Embarcadero Center, Suite 3200, San Francisco, California 94111.

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PROSPECTUS

Digital Realty Trust, Inc.

Common Stock, Preferred Stock, Depositary Shares, Warrants and Guarantees

Digital Realty Trust, L.P.

Debt Securities

We may from time to time offer, in one or more series or classes, separately or together, and in amounts, at prices and on terms to be set forth in one or more supplements to this prospectus, the following securities: (i) shares of Digital Realty Trust, Inc.’s common stock, par value $0.01 per share, (ii) shares of Digital Realty Trust, Inc.’s preferred stock, par value $0.01 per share, (iii) depositary shares representing entitlement to all rights and preferences of fractions of shares of Digital Realty Trust, Inc.’s preferred stock of a specified series and represented by depositary receipts, (iv) warrants to purchase shares of Digital Realty Trust, Inc.’s common stock or preferred stock or depositary shares and (v) debt securities of Digital Realty Trust, L.P. which may be fully and unconditionally guaranteed by Digital Realty Trust, Inc.

This prospectus also covers delayed delivery contracts that may be issued by Digital Realty Trust, Inc. or Digital Realty Trust, L.P. under which the counterparty may be required to purchase common stock, preferred stock, depositary shares or warrants to purchase common stock, preferred stock or depositary shares of Digital Realty Trust, Inc. or debt securities of Digital Realty Trust, L.P. (including guarantees of the debt securities by Digital Realty Trust, Inc.). Delayed delivery contracts may be issued together with the specific securities to which they relate. In addition, securities registered hereunder may be sold separately, together or as units with other securities registered hereunder.

We refer to the common stock, preferred stock, depositary shares, warrants and debt securities (together with any related guarantees) registered hereunder collectively as the “securities” in this prospectus. We will offer our securities in amounts, at prices and on terms determined at the time of the offering of any such security.

The specific terms of each series or class of the securities will be set forth in the applicable prospectus supplement and will include, as applicable: (i) in the case of common stock, any public offering price; (ii) in the case of preferred stock, the specific title and any dividend, liquidation, redemption, conversion, voting and other rights and any public offering price; (iii) in the case of depositary shares, the fractional share of preferred stock represented by each such depositary share; (iv) in the case of warrants, the duration, offering price, exercise price and detachability; and (v) in the case of debt securities and, as applicable, related guarantees, the specific terms of such debt securities and related guarantees. In addition, because Digital Realty Trust, Inc. is organized and conducts its operations so as to qualify as a real estate investment trust, or REIT, for U.S. federal income tax purposes, the specific terms of any securities may include limitations on actual or constructive ownership and restrictions on transfer of the securities, in each case as may be appropriate to preserve Digital Realty Trust, Inc.’s status as a REIT.

The securities may be offered directly by us, through agents designated from time to time by us, or to or through underwriters or dealers. These securities also may be offered by securityholders, if so provided in a prospectus supplement hereto. We will provide specific information about any selling securityholders in one or more supplements to this prospectus. If any agents, dealers or underwriters are involved in the sale of any of the securities, their names, and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, in the applicable prospectus supplement. See the sections entitled “Plan of Distribution” and “About this Prospectus” for more information. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such series of securities.

Digital Realty Trust, Inc.’s common stock, series C preferred stock, series G preferred stock, series H preferred stock, series I preferred stock and series J preferred stock currently trade on the New York Stock Exchange, or NYSE, under the symbols “DLR”, “DLR Pr C”, “DLR Pr G”, “DLR Pr H”, “DLR Pr I” and “DLR Pr J”, respectively.

See “Risk Factors” beginning on page 3 for certain risk factors relevant to an investment in the securities.

Neither the United States Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 22, 2017.

Unless otherwise indicated or unless the context requires otherwise, all references in this prospectus to “we,” “us,” “our,” “our company” or “the company” refer to Digital Realty Trust, Inc., a Maryland corporation, together with its consolidated subsidiaries, including Digital Realty Trust, L.P., a Maryland limited partnership, of which Digital Realty Trust, Inc. is the sole general partner. Unless otherwise indicated or unless the context requires otherwise, all references in this prospectus to “our operating partnership” or “the operating partnership” refer to Digital Realty Trust, L.P. together with its consolidated subsidiaries.

You should rely only on the information contained in this prospectus, in an accompanying prospectus supplement or incorporated by reference herein or therein. We have not authorized anyone to provide you with information or make any representation that is different. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and any accompanying prospectus supplement do not constitute an offer to sell or a solicitation of an offer to buy any securities other than the registered securities to which they relate, and this prospectus and any accompanying prospectus supplement do not constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction where, or to any person to whom, it is unlawful to make such an offer or solicitation. You should not assume that the information contained in this prospectus and any accompanying prospectus supplement is correct on any date after the respective dates of this prospectus and such prospectus supplement or supplements, as applicable, even though this prospectus and such prospectus supplement or supplements are delivered or securities are sold pursuant to this prospectus and such prospectus supplement or supplements at a later date. Since the respective dates of the prospectus contained in this registration statement and any accompanying prospectus supplement, our business, financial condition, results of operations and prospects may have changed. We may only use this prospectus to sell the securities if it is accompanied by a prospectus supplement.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the United States Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this process, we may sell common stock, preferred stock, depositary shares, warrants and debt securities (and related guarantees, as applicable) in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement containing specific information about the terms of the applicable offering. Such prospectus supplement may add, update or change information contained in this prospectus. To the extent that this prospectus is used by any securityholder to resell any securities, information with respect to the securityholder and the terms of the securities being offered will be contained in a prospectus supplement. You should read this prospectus and the applicable prospectus supplement together with the additional information described under the heading “Where You Can Find More Information.”

We or any selling securityholders may offer the securities directly, through agents, or to or through underwriters. The applicable prospectus supplement will describe the terms of the plan of distribution and set forth the names of any agents or underwriters involved in the sale of the securities. See “Plan of Distribution” for more information on this topic. No securities may be sold without delivery of a prospectus supplement describing the method and terms of the offering of those securities.

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OUR COMPANY

We own, acquire, develop and operate data centers. We are focused on providing data center, colocation and interconnection solutions for domestic and international tenants across a variety of industry verticals ranging from financial services, cloud and information technology services, to manufacturing, energy, health care, and consumer products. Digital Realty Trust, L.P., a Maryland limited partnership, is the entity through which Digital Realty Trust, Inc., a Maryland corporation, conducts its business and owns its assets. Digital Realty Trust, Inc. operates as a REIT for U.S. federal income tax purposes.

We are diversified in major metropolitan areas where data center and technology tenants are concentrated, including the Atlanta, Boston, Chicago, Dallas, Los Angeles, New York, Northern Virginia, Phoenix, San Francisco, Seattle and Silicon Valley metropolitan areas in the United States, the Amsterdam, Dublin, Frankfurt, London and Paris metropolitan areas in Europe and the Singapore, Sydney, Melbourne, Hong Kong and Osaka metropolitan areas in the Asia Pacific region. The types of properties within our portfolio include:

Unlike traditional office and flex/research and development space, the location of and improvements to our facilities, including network density, interconnection infrastructure and connectivity-centric customers in certain of our facilities, are generally essential to our tenants’ businesses, which we believe results in high occupancy levels, longer average lease terms and customer relationships and lower turnover. In addition, many of our properties have tenant improvements that have been installed at our tenants’ expense. The tenant improvements in our facilities are generally readily adaptable for use by similar tenants.

Digital Realty Trust, Inc. was incorporated in the state of Maryland on March 9, 2004. Digital Realty Trust, L.P. was organized in the state of Maryland on July 21, 2004. Our principal executive offices are located at Four Embarcadero Center, Suite 3200, San Francisco, California 94111. Our telephone number at that location is (415) 738-6500. Our website is located at www.digitalrealty.com. The information found on, or otherwise accessible through, our website is not incorporated into, and does not form a part of, this prospectus or any other report or document we file with or furnish to the SEC.

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RISK FACTORS

Investment in any securities offered pursuant to this prospectus involves risks. Before acquiring any offered securities pursuant to this prospectus, you should carefully consider the information contained or incorporated by reference in this prospectus or in any accompanying prospectus supplement, including, without limitation, the risk factors incorporated by reference to the company’s and the operating partnership’s most recent combined Annual Report on Form 10-K, and the other information contained or incorporated by reference in this prospectus, as updated by our subsequent filings under the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement before acquiring any of such securities. The occurrence of any of these risks might cause you to lose all or a part of your investment in the offered securities. Please also refer to the section below entitled “Forward-Looking Statements.”

3

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s public reference room at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the public reference room. The SEC also maintains a web site that contains reports, proxy and information statements and other information regarding registrants that file electronically with the SEC at www.sec.gov. You can inspect reports and other information that Digital Realty Trust, Inc. files at the offices of the NYSE, 20 Broad Street, New York, New York 10005. In addition, we maintain a website that contains information about us at www.digitalrealty.com. The information found on, or otherwise accessible through, this website is not incorporated into, and does not form a part of, this prospectus or any other report or document we file with or furnish to the SEC.

We have filed with the SEC a registration statement on Form S-3, of which this prospectus is a part, including exhibits, schedules and amendments filed with, or incorporated by reference in, this registration statement, under the Securities Act of 1933, as amended, or the Securities Act, with respect to the securities registered hereby. This prospectus and any accompanying prospectus supplement do not contain all of the information set forth in the registration statement and exhibits and schedules to the registration statement. For further information with respect to our company and the securities registered hereby, reference is made to the registration statement, including the exhibits to the registration statement. Statements contained in this prospectus and any accompanying prospectus supplement as to the contents of any contract or other document referred to, or incorporated by reference in, this prospectus and any accompanying prospectus supplement are not necessarily complete and, where that contract is an exhibit to the registration statement, each statement is qualified in all respects by the exhibit to which the reference relates. Copies of the registration statement, including the exhibits and schedules to the registration statement, may be examined at the SEC’s public reference room. Copies of all or a portion of the registration statement can be obtained from the public reference room of the SEC upon payment of prescribed fees. This registration statement is also available to you on the SEC’s website.

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INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” in this prospectus the information we file with the SEC, which means that we can disclose important information to you by referring to those documents. The information incorporated by reference is an important part of this prospectus. The incorporated documents contain significant information about us, our business and our finances. Any statement contained in a document which is incorporated by reference in this prospectus is automatically updated and superseded if information contained in this prospectus, or information that we later file with the SEC, modifies or replaces this information. We incorporate by reference the following documents we filed with the SEC:

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We will provide without charge to each person, including any beneficial owner, to whom a prospectus is delivered, on written or oral request of that person, a copy of any or all of the documents we are incorporating by reference into this prospectus, other than exhibits to those documents unless those exhibits are specifically incorporated by reference into those documents. A written request should be addressed to Investor Relations, Digital Realty Trust, Inc., Four Embarcadero Center, Suite 3200, San Francisco, California 94111.

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FORWARD-LOOKING STATEMENTS

This prospectus, including the documents that we incorporate by reference, contains “forward-looking statements” within the meaning of the federal securities laws. Also, documents we subsequently file with the SEC and incorporate by reference will contain forward-looking statements. In particular, statements pertaining to our capital resources, portfolio performance and results of operations contain forward-looking statements. Likewise, all of our statements regarding anticipated market conditions, demographics and results of operations are forward-looking statements.

Forward-looking statements involve numerous risks and uncertainties and you should not rely on them as predictions of future events. Forward-looking statements depend on assumptions, data or methods which may be incorrect or imprecise and we may not be able to realize them. We do not guarantee that the transactions and events described will happen as described or that they will happen at all. You can identify forward-looking statements by the use of forward-looking terminology such as “believes,” “expects,” “may,” “will,” “should,” “seeks,” “approximately,” “intends,” “plans,” “pro forma,” “estimates” or “anticipates” or the negative of these words and phrases or similar words or phrases which are predictions of or indicate future events or trends and discussions which do not relate solely to historical matters. You can also identify forward-looking statements by discussions of strategy, plans or intentions. The following factors, among others, could cause actual results and future events to differ materially from those set forth or contemplated in the forward-looking statements:

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For a further discussion of these and other factors that could impact our future results, performance or transactions, see the section entitled “Risk Factors,” including the risks incorporated therein, from Digital Realty Trust, Inc.’s and Digital Realty Trust, L.P.’s most recent combined Annual Report on Form 10-K, as updated by our subsequent filings, including filings we make after the date of this prospectus. While forward-looking statements reflect our good faith beliefs, they are not guaranties of future performance. We disclaim any obligation to publicly update or revise any forward-looking statement to reflect changes in underlying assumptions or factors, new information, data or methods, future events or other changes.

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USE OF PROCEEDS

Unless otherwise indicated in the applicable prospectus supplement, Digital Realty Trust, Inc. intends to contribute the net proceeds from any sale of common stock, preferred stock, depositary shares or warrants pursuant to this prospectus to our operating partnership. Unless otherwise indicated in the applicable prospectus supplement, our operating partnership intends to use such net proceeds received from Digital Realty Trust, Inc. and any net proceeds from any sale of debt securities pursuant to this prospectus for general corporate purposes, including, the repayment of outstanding indebtedness, the repurchase, redemption or retirement of outstanding debt or equity securities, and the funding of development and acquisition opportunities.

Pending application of cash proceeds, our operating partnership may use the net proceeds to temporarily reduce borrowings under our global revolving credit facility or we may invest the net proceeds in interest-bearing accounts and short-term, interest-bearing securities which are consistent with Digital Realty Trust, Inc.’s intention to qualify as a REIT for U.S. federal income tax purposes.

We will not receive any of the proceeds from sales of securities by selling securityholders, if any, pursuant to this prospectus.

Further details regarding the use of the net proceeds of a specific series or class of the securities will be set forth in the applicable prospectus supplement.

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RATIO OF EARNINGS TO FIXED CHARGES AND PREFERRED DIVIDENDS

Our ratios of earnings to fixed charges and earnings to fixed charges and preferred dividends for the periods indicated are as follows:

Digital Realty Trust, Inc.

Digital Realty Trust, Inc.’s ratios of earnings to fixed charges are computed by dividing earnings by fixed charges. Digital Realty Trust, Inc.’s ratios of earnings to fixed charges and preferred dividends are computed by dividing earnings by the sum of fixed charges and preferred dividends. For this purpose, “earnings” consist of income from continuing operations before noncontrolling interests and fixed charges. “Fixed charges” consist of interest expense, capitalized interest and amortization of deferred financing fees, whether expensed or capitalized, and interest within rental expense. “Preferred stock dividends” consist of the amount of pre-tax earnings required to pay dividends on Digital Realty Trust, Inc.’s series C convertible preferred stock (which was converted to common stock of Digital Realty Trust, Inc. on April 17, 2012), series D convertible preferred stock (which was converted to common stock on February 26, 2013), series E preferred stock (which was redeemed on September 15, 2016), series F preferred stock (which was redeemed on April 5, 2017), series G preferred stock, series H preferred stock and series I preferred stock.

Digital Realty Trust, L.P.

Digital Realty Trust, L.P.’s ratios of earnings to fixed charges are computed by dividing earnings by fixed charges. Digital Realty Trust, L.P.’s ratios of earnings to fixed charges and preferred unit distributions are computed by dividing earnings by the sum of fixed charges and preferred unit distributions. For this purpose, “earnings” consist of income from continuing operations before noncontrolling interests and fixed charges. “Fixed charges” consist of interest expense, capitalized interest and amortization of deferred financing fees, whether expensed or capitalized, and interest within rental expense. “Preferred unit distributions” consist of the amount of pre-tax earnings required to pay distributions on Digital Realty Trust, L.P.’s series C convertible preferred units (which were converted to common units of Digital Realty Trust, L.P. on April 17, 2012), series D convertible preferred units (which were converted to common units on February 26, 2013), series E preferred units (which were redeemed on September 15, 2016), series F preferred units (which were redeemed on April 5, 2017), series G preferred units, series H preferred units and series I preferred units.

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GENERAL DESCRIPTION OF SECURITIES

We or any selling securityholders named in a prospectus supplement directly or through agents, dealers or underwriters designated from time to time, may from time to time offer, issue and sell, together or separately, under this prospectus one or more of the following categories of securities:

We may issue Digital Realty Trust, L.P.’s debt securities, and related guarantees thereof by Digital Realty Trust, Inc., as exchangeable for and/or convertible into shares of Digital Realty Trust, Inc.’s common stock, preferred stock and/or other securities and related guarantees. Digital Realty Trust, Inc.’s preferred stock may also be exchangeable for and/or convertible into shares of its common stock, another series of its preferred stock, or its other securities. Digital Realty Trust, L.P.’s debt securities and related guarantees by Digital Realty Trust, Inc., and Digital Realty Trust, Inc.’s preferred stock, common stock, depositary shares and warrants are collectively referred to in this prospectus as the “securities.” When a particular series of securities is offered, a supplement to this prospectus will be delivered with this prospectus, which will set forth the terms of the offering and sale of the offered securities.

For purposes of the sections below entitled “Description of Common Stock,” “Description of Preferred Stock,” “Description of Depositary Shares,” “Description of Warrants,” and “Description of Debt Securities and Related Guarantees” references to “the company,” and “our company” refer only to Digital Realty Trust, Inc. and not to Digital Realty Trust, L.P. or its other subsidiaries.

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DESCRIPTION OF COMMON STOCK

The following description of Digital Realty Trust, Inc.’s common stock sets forth certain general terms and provisions of the common stock to which any prospectus supplement may relate and will apply to the common stock offered by this prospectus unless we provide otherwise in the applicable prospectus supplement. The description of Digital Realty Trust, Inc.’s common stock set forth below and in any prospectus supplement does not purport to be complete and is subject to and qualified in its entirety by reference to the applicable provisions of Digital Realty Trust, Inc.’s charter and bylaws.

General. The company’s charter provides that it may issue up to 315 million shares of its common stock, par value $0.01 per share, or the common stock. As of September 21, 2017, 205,164,931 shares of the common stock were issued and outstanding, excluding:

All outstanding shares of the common stock are duly authorized, fully paid and nonassessable. Subject to the preferential rights of any other class or series of stock and to the provisions of the company’s charter regarding the restrictions on transfer of stock, holders of shares of the common stock are entitled to receive dividends on such stock if, as and when authorized by the company’s board of directors out of assets legally available therefor and declared by the company and to share ratably in the assets of the company legally available for distribution to the company’s stockholders in the event of the company’s liquidation, dissolution or winding up after payment or establishment of reserves for all known debts and liabilities of the company.

Subject to the provisions of the company’s charter regarding the restrictions on transfer of stock and except as may be otherwise specified therein with respect to any class or series of common stock, each outstanding share of the common stock entitles the holder to one vote on all matters submitted to a vote of stockholders, including the election of directors and, except as provided with respect to any other class or series of stock, the holders of such shares will possess the exclusive voting power. There is no cumulative voting in the election of the company’s board of directors, which means that the holders of a majority of the outstanding shares of the common stock can elect all of the directors then standing for election and the holders of the remaining shares will not be able to elect any directors.

Holders of shares of the common stock have no preference, conversion, exchange, sinking fund or redemption rights, have no preemptive rights to subscribe for any securities of the company and generally have no appraisal

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rights unless the company’s board of directors determines that appraisal rights apply, with respect to all or any classes or series of stock, to one or more transactions occurring after the date of such determination in connection with which stockholders would otherwise be entitled to exercise appraisal rights. Subject to the provisions of the company’s charter regarding the restrictions on transfer of stock, shares of the common stock will have equal dividend, liquidation and other rights.

Under the Maryland General Corporation Law, or MGCL, a Maryland corporation generally cannot dissolve, amend its charter, merge, convert, sell all or substantially all of its assets, engage in a share exchange or engage in similar transactions outside the ordinary course of business unless the action is approved by the affirmative vote of stockholders entitled to cast at least two-thirds of the votes entitled to be cast on the matter unless a lesser percentage (but not less than a majority of all of the votes entitled to be cast on the matter) is set forth in the corporation’s charter. Except for certain charter amendments relating to the removal of directors and the vote required for certain amendments, the company’s charter provides that these actions may be taken if declared advisable by a majority of the company’s board of directors and approved by the vote of stockholders entitled to cast a majority of the votes entitled to be cast on the matter. However, Maryland law permits a corporation to transfer all or substantially all of its assets without the approval of the stockholders of the corporation to one or more persons if all of the equity interests of the person or persons are owned, directly or indirectly, by the corporation. In addition, operating assets may be held by a corporation’s subsidiaries, as in the company’s situation, and these subsidiaries may be able to transfer all or substantially all of such assets without a vote of the parent corporation’s stockholders.

The company’s charter authorizes its board of directors to reclassify any unissued shares of the common stock into other classes or series of stock and to establish the number of shares in each class or series and to set the preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications or terms or conditions of redemption for each such class or series.

Power to Increase Authorized Stock and Issue Additional Shares of the Common Stock

The company’s board of directors has the power to amend the company’s charter from time to time without stockholder approval to increase or decrease the number of authorized shares of common stock, to issue additional authorized but unissued shares of the common stock and to classify or reclassify unissued shares of the common stock into other classes or series of stock and thereafter to cause the company to issue such classified or reclassified shares of stock. The company believes these powers provide it with increased flexibility in structuring possible future financings and acquisitions and in meeting other needs which might arise. Subject to the limited rights of holders of the company’s series C preferred stock, series G preferred stock, series H preferred stock, series I preferred stock and series J preferred stock and each other parity class or series of preferred stock, voting together as a single class, to approve certain issuances of senior classes or series of stock, the additional classes or series, as well as the common stock, will be available for issuance without further action by the company’s stockholders, unless stockholder consent is required by applicable law or the rules of any stock exchange or automated quotation system on which the company’s securities may be listed or traded. Although the company’s board of directors does not intend to do so, it could authorize us to issue a class or series that could, depending upon the terms of the particular class or series, delay, defer or prevent a transaction or a change of control of the company that might involve a premium price for the company’s stockholders or otherwise be in their best interest.

Restrictions on Ownership and Transfer

To assist us in complying with certain U.S. federal income tax requirements applicable to REITs, the company has adopted certain restrictions relating to the ownership and transfer of the common stock. See “Restrictions on Ownership and Transfer.”

Transfer Agent and Registrar

The transfer agent and registrar for the common stock is American Stock Transfer & Trust Company, LLC.

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DESCRIPTION OF PREFERRED STOCK

The specific terms of a particular class or series of preferred stock will be described in the prospectus supplement relating to that class or series, including a prospectus supplement providing that preferred stock may be issuable upon the exercise of warrants the company issues. The description of preferred stock set forth below and the description of the terms of a particular class or series of preferred stock set forth in the applicable prospectus supplement do not purport to be complete and are qualified in their entirety by reference to the articles supplementary relating to that class or series.

General

The company’s charter provides that it may issue up to 110 million shares of preferred stock, $0.01 par value per share, or preferred stock. The company’s charter authorizes its board of directors to amend its charter from time to time without stockholder approval to increase the number of authorized shares of preferred stock. As of September 21, 2017, 8,050,000 shares of the company’s series C preferred stock, 10,000,000 shares of the company’s series G preferred stock, 14,600,000 shares of the company’s series H preferred stock, 10,000,000 shares of the company’s series I preferred stock and 8,000,000 shares of the company’s series J preferred stock were issued and outstanding. No other shares of the company’s preferred stock are currently outstanding.

The company’s charter authorizes its board of directors to classify any unissued shares of preferred stock and to reclassify any previously classified but unissued shares of any series into other classes or series of stock. Prior to the issuance of shares of each class or series, the company’s board of directors is required by the MGCL and the company’s charter to set, subject to the provisions of the company’s charter regarding the restrictions on transfers of stock, the terms, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms or conditions of redemption for each such class or series. Thus, the company’s board of directors could authorize the issuance of shares of preferred stock with terms and conditions which could have the effect of delaying, deferring or preventing a transaction or a change of control of the company that might involve a premium price for holders of the common stock or otherwise be in their best interest.

The preferences and other terms of the preferred stock of each class or series will be fixed by the articles supplementary relating to such class or series. A prospectus supplement, relating to each class or series, will describe the terms of the preferred stock, including, where applicable, the following:

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Rank

Unless otherwise specified in the applicable prospectus supplement, the preferred stock will, with respect to dividend rights and rights upon liquidation, dissolution or winding up of the company, rank: (i) senior to all classes or series of the common stock, and to any other class or series of the company’s stock expressly designated as ranking junior to the preferred stock; (ii) on parity with any class or series of the company’s stock expressly designated as ranking on parity with the preferred stock; and (iii) junior to any other class or series of the company’s stock expressly designated as ranking senior to the preferred stock.

Conversion Rights

The terms and conditions, if any, upon which any shares of any class or series of preferred stock are convertible into the common stock will be described in the applicable prospectus supplement relating thereto. Such terms will include the number of shares of the common stock into which the shares of preferred stock are convertible, the conversion price (or manner of calculation thereof), the conversion period, provisions as to whether conversion will be at the option of the holders of such class or series of preferred stock, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of such class or series of preferred stock.

Power to Increase Authorized Stock and Issue Additional Shares of Preferred Stock

The company’s board of directors has the power to amend the company’s charter from time to time without stockholder approval to increase the number of authorized shares of preferred stock, to issue additional authorized but unissued shares of the company’s preferred stock and to classify or reclassify unissued shares of the company’s preferred stock into other classes or series of stock and thereafter to cause us to issue such classified or reclassified shares of stock. Subject to the limited rights of holders of the company’s series C preferred stock, series G preferred stock, series H preferred stock, series I preferred stock and series J preferred stock and each other parity class or series of preferred stock, voting together as a single class, to approve certain issuances of senior classes or series of stock, the additional classes or series will be available for issuance without further action by the company’s stockholders, unless stockholder consent is required by applicable law or the rules of any stock exchange or automated quotation system on which the company’s securities may be listed or traded. Although the company’s board of directors does not intend to do so, it could authorize the company to issue a class or series that could, depending upon the terms of the particular class or series, delay, defer or prevent a transaction or a change of control of the company that might involve a premium price for the company’s stockholders or otherwise be in their best interest.

Restrictions on Ownership and Transfer

To assist the company in complying with certain U.S. federal income tax requirements applicable to REITs, the company has adopted certain restrictions relating to the ownership and transfer of the company’s series C

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preferred stock, series G preferred stock, series H preferred stock, series I preferred stock and series J preferred stock. The company expects to adopt similar restrictions with respect to any class or series offered pursuant to this prospectus under the articles supplementary for each such class or series. The applicable prospectus supplement will specify any additional ownership limitation relating to such class or series. See “Restrictions on Ownership and Transfer.”

6.625% Series C Cumulative Redeemable Perpetual Preferred Stock

General

The company’s board of directors approved articles supplementary, a copy of which has been previously filed with the SEC and which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part, creating the series C preferred stock as a series of the company’s preferred stock, designated as the 6.625% Series C Cumulative Redeemable Perpetual Preferred Stock. The following description of the series C preferred stock is qualified in its entirety by reference to such articles supplementary and the company’s charter. The series C preferred stock is validly issued, fully paid and nonassessable

The series C preferred stock is currently listed on the NYSE as “DLR Pr C”.

Ranking

The series C preferred stock ranks, with respect to dividend rights and rights upon the company’s liquidation, dissolution or winding-up:

Dividend Rate and Payment Date

Holders are entitled to receive cumulative cash dividends on the series C preferred stock from and including the date of original issue, payable quarterly in arrears on or about the last calendar day of March, June, September and December of each year at the rate of 6.625% per annum of the $25.00 liquidation preference per share (equivalent to an annual amount of $1.65625 per share). Dividends on the series C preferred stock will accrue whether or not the company has earnings, whether or not there are funds legally available for the payment of such dividends and whether or not such dividends are authorized or declared.

Liquidation Preference

In the event of a liquidation, dissolution or winding up, holders of the series C preferred stock will have the right to receive $25.00 per share, plus accrued and unpaid dividends (whether or not earned or declared) up to but excluding the date of payment, before any payment is made to holders of the common stock and any other class or series of stock ranking junior to the series C preferred stock as to liquidation rights. The rights of holders of series C preferred stock to receive their liquidation preference will be subject to the proportionate rights of any other class or series of stock ranking on parity with the series C preferred stock as to liquidation.

Optional Redemption

The series C preferred stock may not be redeemed prior to May 15, 2021, except in limited circumstances to preserve the company’s status as a REIT and pursuant to the special optional redemption right described below.

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On and after May 15, 2021, the series C preferred stock will be redeemable at the company’s option, in whole or in part at any time or from time to time, for cash at a redemption price of $25.00 per share, plus accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the redemption date. However, unless full cumulative dividends on the series C preferred stock for all past dividend periods have been, or contemporaneously are, paid or an amount in cash sufficient for the payment thereof is set apart, no shares of series C preferred stock may be redeemed; provided, that the foregoing restriction does not prevent DLR from taking action necessary to preserve its status as a REIT. Any partial redemption will be on a pro rata basis.

Special Optional Redemption

Upon the occurrence of a Change of Control, the company may, at its option, redeem the series C preferred stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date (as defined below), the company exercises any of its redemption rights relating to the series C preferred stock (whether its optional redemption right or its special optional redemption right), the holders of series C preferred stock will not have the conversion right described below.

A “Change of Control” is when, after the original issuance of the series G preferred stock, the following have occurred and are continuing:

No Maturity, Sinking Fund or Mandatory Redemption

The series C preferred stock has no stated maturity date and the company is not required to redeem the series C preferred stock at any time. Accordingly, the series C preferred stock will remain outstanding indefinitely, unless the company decides, at its option, to exercise its redemption right or, under circumstances where the holders of the series C preferred stock have a conversion right, such holders decide to convert the series C preferred stock into common stock. The series C preferred stock is not subject to any sinking fund.

Voting Rights

Holders of series C preferred stock generally have no voting rights. However, if the company is in arrears on dividends on the series C preferred stock for six or more quarterly periods, whether or not consecutive, holders of the series C preferred stock (voting together as a class with the holders of all other classes or series of parity preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote at a special meeting called upon the written request of at least 10% of such holders or at the next annual meeting of stockholders and each subsequent annual meeting of stockholders for the election of two additional directors to serve on the company’s board of directors until all accumulated dividends with respect to the series C preferred stock and any other class or series of parity preferred stock have been fully paid. In addition, the company may

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not make certain material and adverse changes to the terms of the series C preferred stock without the affirmative vote of the holders of at least two-thirds of the outstanding shares of series C preferred stock and all other shares of any class or series ranking on parity with the series C preferred stock that are entitled to similar voting rights (voting together as a single class).

Conversion

Upon the occurrence of a Change of Control, each holder of series C preferred stock will have the right (unless, prior to the Change of Control Conversion Date, the company has provided or provides notice of its election to redeem the series C preferred stock) to convert some or all of the series C preferred stock held by such holder on the date the series of C preferred stock is to be converted, which we refer to as the Change of Control Conversion Date, into a number of shares of common stock per share of series C preferred stock to be converted equal to the lesser of:

subject, in each case, to provisions for the receipt of alternative consideration as described in the articles supplementary relating to the series C preferred stock.

The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of common stock is solely cash, the amount of cash consideration per share of common stock, (ii) if the consideration to be received in the Change of Control by holders of common stock is other than solely cash, the average of the closing price per share of common stock on the ten consecutive trading days immediately preceding, but not including, the effective date of such Change of Control and (iii) if there is not a readily determinable closing price for the common stock, the fair market value of such other consideration received in the Change of Control per share of common stock as determined by the company’s board or a committee thereof.

If, prior to the Change of Control Conversion Date, the company has provided or provides a redemption notice, whether pursuant to its special optional redemption right in connection with a Change of Control or its optional redemption right, holders of series C preferred stock will not have any right to convert the series C preferred stock into shares of the company’s common stock in connection with the Change of Control and any shares of series C preferred stock selected for redemption that have been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Change of Control Conversion Date.

Except as provided above in connection with a Change of Control, the series C preferred stock is not be convertible into or exchangeable for any other securities or property.

Transfer Agent and Registrar

The transfer agent and registrar for the series C preferred stock is American Stock Transfer & Trust Company, LLC. 

5.875% Series G Cumulative Redeemable Preferred Stock

General

The company’s board of directors and a duly authorized committee thereof approved articles supplementary, a copy of which has been previously filed with the SEC and which is incorporated by reference as an exhibit to the

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registration statement of which this prospectus is a part, creating the series G preferred stock as a series of the company’s preferred stock, designated as the 5.875% Series G Cumulative Redeemable Preferred Stock. The series G preferred stock is validly issued, fully paid and nonassessable.

The series G preferred stock is currently listed on the NYSE as “DLR Pr G”.

Ranking

The series G preferred stock ranks, with respect to dividend rights and rights upon the company’s liquidation, dissolution or winding-up:

Dividend Rate and Payment Date

Holders are entitled to receive cumulative cash dividends on the series G preferred stock from and including the date of original issue, payable quarterly in arrears on or about the last calendar day of March, June, September and December of each year, at the rate of 5.875% per annum of the $25.00 liquidation preference per share (equivalent to an annual amount of $1.46875 per share). Dividends on the series G preferred stock will accrue whether or not the company has earnings, whether or not there are funds legally available for the payment of such dividends and whether or not such dividends are authorized or declared.

Liquidation Preference

If the company liquidates, dissolves or winds up, holders of the series G preferred stock will have the right to receive $25.00 per share, plus accrued and unpaid dividends (whether or not earned or declared) up to but excluding the date of payment, before any payment is made to holders of the common stock and any other class or series of stock ranking junior to the series G preferred stock as to liquidation rights. The rights of holders of series G preferred stock to receive their liquidation preference will be subject to the proportionate rights of any other class or series of the company’s stock ranking on parity with the series G preferred stock as to liquidation.

Optional Redemption

The company may not redeem the series G preferred stock prior to April 9, 2018, except in limited circumstances to preserve the company’s status as a REIT and pursuant to the special optional redemption right described below. On and after April 9, 2018, the series G preferred stock will be redeemable at the company’s option, in whole or in part at any time or from time to time, for cash at a redemption price of $25.00 per share, plus accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the redemption date. However, unless full cumulative dividends on the series G preferred stock for all past dividend periods have been, or contemporaneously are, paid or an amount in cash sufficient for the payment thereof is set apart by the company, no shares of series G preferred stock may be redeemed unless all outstanding shares of series G preferred stock are simultaneously redeemed; provided, that the foregoing restriction does not prevent the company from taking action necessary to preserve the company’s status as a REIT. Any partial redemption will be on a pro rata basis.

Special Optional Redemption

Upon the occurrence of a Change of Control (as defined below), the company may, at its option, redeem the series G preferred stock, in whole or in part within 120 days after the first date on which such Change of Control

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occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date (as defined below), the company exercises any of its redemption rights relating to the series G preferred stock (whether its optional redemption right or its special optional redemption right), the holders of series G preferred stock will not have the conversion right described below.

A “Change of Control” is when, after the original issuance of the series G preferred stock, the following have occurred and are continuing:

No Maturity, Sinking Fund or Mandatory Redemption

The series G preferred stock has no stated maturity date and the company is not required to redeem the series G preferred stock at any time. Accordingly, the series G preferred stock will remain outstanding indefinitely, unless the company decides, at its option, to exercise its redemption right or, under circumstances where the holders of the series G preferred stock have a conversion right, such holders decide to convert the series G preferred stock into the company’s common stock. The series G preferred stock is not subject to any sinking fund.

Voting Rights

Holders of series G preferred stock generally have no voting rights. However, if the company is in arrears on dividends on the series G preferred stock for six or more quarterly periods, whether or not consecutive, holders of the series G preferred stock (voting together as a class with the holders of all other classes or series of parity preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote at a special meeting called upon the written request of at least 10% of such holders or at the company’s next annual meeting and each subsequent annual meeting of stockholders for the election of two additional directors to serve on the company’s board of directors until all unpaid dividends with respect to the series G preferred stock and any other class or series of parity preferred stock have been paid or declared and a sum sufficient for the payment thereof set aside for payment. In addition, the company may not make certain material and adverse changes to the terms of the series G preferred stock without the affirmative vote of the holders of at least two-thirds of the outstanding shares of series G preferred stock and all other shares of any class or series ranking on parity with the series G preferred stock that are entitled to similar voting rights (voting together as a single class).

Conversion

Upon the occurrence of a Change of Control, each holder of series G preferred stock will have the right (unless, prior to the Change of Control Conversion Date, the company has provided or provides notice of its election to redeem the series G preferred stock) to convert some or all of the series G preferred stock held by such holder on the date the series of G preferred stock is to be converted, which we refer to as the Change of Control Conversion

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Date, into a number of shares of the company’s common stock per share of series G preferred stock to be converted equal to the lesser of:

subject, in each case, to provisions for the receipt of alternative consideration as described in the articles supplementary relating to the Series G preferred stock.

The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of the company’s common stock is solely cash, the amount of cash consideration per share of the company’s common stock or (ii) if the consideration to be received in the Change of Control by holders of the company’s common stock is other than solely cash (x) the average of the closing sale prices per share of the company’s common stock (or, if no closing sale price is reported, the average of the closing bid and ask prices or, if more than one in either case, the average of the average closing bid and the average closing ask prices) for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control as reported on the principal U.S. securities exchange on which the company’s common stock is then traded, or (y) the average of the last quoted bid prices for the company’s common stock in the over-the-counter market as reported by Pink Sheets LLC or similar organization for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control, if the company’s common stock is not then listed for trading on a U.S. securities exchange.

If, prior to the Change of Control Conversion Date, the company has provided or provides a redemption notice, whether pursuant to its special optional redemption right in connection with a Change of Control or its optional redemption right, holders of series G preferred stock will not have any right to convert the series G preferred stock into shares of the company’s common stock in connection with the Change of Control and any shares of series G preferred stock selected for redemption that have been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Change of Control Conversion Date.

Except as provided above in connection with a Change of Control, the series G preferred stock is not convertible into or exchangeable for any other securities or property.

Transfer Agent and Registrar

The transfer agent and registrar for the company’s series G preferred stock is American Stock Transfer & Trust Company, LLC.

7.375% Series H Cumulative Redeemable Preferred Stock

General

The company’s board of directors and a duly authorized committee thereof approved articles supplementary, a copy of which has been previously filed with the SEC and which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part, creating the series H preferred stock as a series of the company’s preferred stock, designated as the 7.375% Series H Cumulative Redeemable Preferred Stock. The series H preferred stock is validly issued, fully paid and nonassessable.

The series H preferred stock is currently listed on the NYSE as “DLR Pr H”.

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Ranking

The series H preferred stock ranks, with respect to dividend rights and rights upon the company’s liquidation, dissolution or winding-up:

Dividend Rate and Payment Date

Holders are entitled to receive cumulative cash dividends on the series H preferred stock from and including the date of original issue, payable quarterly in arrears on or about the last calendar day of March, June, September and December of each year, at the rate of 7.375% per annum of the $25.00 liquidation preference per share (equivalent to an annual amount of $1.84375 per share). Dividends on the series H preferred stock will accrue whether or not the company has earnings, whether or not there are funds legally available for the payment of such dividends and whether or not such dividends are authorized or declared.

Liquidation Preference

If the company liquidates, dissolves or winds up, holders of the series H preferred stock will have the right to receive $25.00 per share, plus accrued and unpaid dividends (whether or not earned or declared) up to but excluding the date of payment, before any payment is made to holders of the common stock and any other class or series of stock ranking junior to the series H preferred stock as to liquidation rights. The rights of holders of series H preferred stock to receive their liquidation preference will be subject to the proportionate rights of any other class or series of the company’s stock ranking on parity with the series H preferred stock as to liquidation.

Optional Redemption

The company may not redeem the series H preferred stock prior to March 26, 2019, except in limited circumstances to preserve the company’s status as a REIT and pursuant to the special optional redemption right described below. On and after March 26, 2019, the series H preferred stock will be redeemable at the company’s option, in whole or in part at any time or from time to time, for cash at a redemption price of $25.00 per share, plus accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the redemption date. However, unless full cumulative dividends on the series H preferred stock for all past dividend periods have been, or contemporaneously are, paid or an amount in cash sufficient for the payment thereof is set apart by the company, no shares of series H preferred stock may be redeemed unless all outstanding shares of series H preferred stock are simultaneously redeemed; provided, that the foregoing restriction does not prevent the company from taking action necessary to preserve the company’s status as a REIT. Any partial redemption will be on a pro rata basis.

Special Optional Redemption

Upon the occurrence of a Change of Control (as defined below), the company may, at its option, redeem the series H preferred stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date (as defined below), the company exercises any of its redemption rights relating to the series H preferred stock (whether its optional redemption right or its special optional redemption right), the holders of series H preferred stock will not have the conversion right described below.

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A “Change of Control” is when, after the original issuance of the series H preferred stock, the following have occurred and are continuing:

No Maturity, Sinking Fund or Mandatory Redemption

The series H preferred stock has no stated maturity date and the company is not required to redeem the series H preferred stock at any time. Accordingly, the series H preferred stock will remain outstanding indefinitely, unless the company decides, at its option, to exercise its redemption right or, under circumstances where the holders of the series H preferred stock have a conversion right, such holders decide to convert the series H preferred stock into the company’s common stock. The series H preferred stock is not subject to any sinking fund.

Voting Rights

Holders of series H preferred stock generally have no voting rights. However, if the company is in arrears on dividends on the series H preferred stock for six or more quarterly periods, whether or not consecutive, holders of the series H preferred stock (voting together as a class with the holders of all other classes or series of parity preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote at a special meeting called upon the written request of at least 10% of such holders or at the company’s next annual meeting and each subsequent annual meeting of stockholders for the election of two additional directors to serve on the company’s board of directors until all unpaid dividends with respect to the series H preferred stock and any other class or series of parity preferred stock have been paid or declared and a sum sufficient for the payment thereof set aside for payment. In addition, the company may not make certain material and adverse changes to the terms of the series H preferred stock without the affirmative vote of the holders of at least two-thirds of the outstanding shares of series H preferred stock and all other shares of any class or series ranking on parity with the series H preferred stock that are entitled to similar voting rights (voting together as a single class).

Conversion

Upon the occurrence of a Change of Control, each holder of series H preferred stock will have the right (unless, prior to the Change of Control Conversion Date, the company has provided or provides notice of its election to redeem the series H preferred stock) to convert some or all of the series H preferred stock held by such holder on the date the series of H preferred stock is to be converted, which we refer to as the Change of Control Conversion Date, into a number of shares of the company’s common stock per share of series H preferred stock to be converted equal to the lesser of:

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subject, in each case, to provisions for the receipt of alternative consideration as described in the articles supplementary relating to the Series H preferred stock.

The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of the company’s common stock is solely cash, the amount of cash consideration per share of the company’s common stock or (ii) if the consideration to be received in the Change of Control by holders of the company’s common stock is other than solely cash (x) the average of the closing sale prices per share of the company’s common stock (or, if no closing sale price is reported, the average of the closing bid and ask prices or, if more than one in either case, the average of the average closing bid and the average closing ask prices) for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control as reported on the principal U.S. securities exchange on which the company’s common stock is then traded, or (y) the average of the last quoted bid prices for the company’s common stock in the over-the-counter market as reported by Pink Sheets LLC or similar organization for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control, if the company’s common stock is not then listed for trading on a U.S. securities exchange.

If, prior to the Change of Control Conversion Date, the company has provided or provides a redemption notice, whether pursuant to its special optional redemption right in connection with a Change of Control or its optional redemption right, holders of series H preferred stock will not have any right to convert the series H preferred stock into shares of the company’s common stock in connection with the Change of Control and any shares of series H preferred stock selected for redemption that have been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Change of Control Conversion Date.

Except as provided above in connection with a Change of Control, the series H preferred stock is not convertible into or exchangeable for any other securities or property.

Transfer Agent and Registrar

The transfer agent and registrar for the company’s series H preferred stock is American Stock Transfer & Trust Company, LLC.

6.350% Series I Cumulative Redeemable Preferred Stock

General

The company’s board of directors and a duly authorized committee thereof approved articles supplementary, a copy of which has been previously filed with the SEC and which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part, creating the series I preferred stock as a series of the company’s preferred stock, designated as the 6.350% Series I Cumulative Redeemable Preferred Stock. The series I preferred stock is validly issued, fully paid and nonassessable.

The series I preferred stock is currently listed on the NYSE as “DLR Pr I”.

Ranking

The series I preferred stock ranks, with respect to dividend rights and rights upon the company’s liquidation, dissolution or winding-up:

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Dividend Rate and Payment Date

Holders are entitled to receive cumulative cash dividends on the series I preferred stock from and including the date of original issue, payable quarterly in arrears on or about the last calendar day of March, June, September and December of each year, at the rate of 6.350% per annum of the $25.00 liquidation preference per share (equivalent to an annual amount of $1.5875 per share). Dividends on the series I preferred stock will accrue whether or not the company has earnings, whether or not there are funds legally available for the payment of such dividends and whether or not such dividends are authorized or declared.

Liquidation Preference

If the company liquidates, dissolves or winds up, holders of the series I preferred stock will have the right to receive $25.00 per share, plus accrued and unpaid dividends (whether or not earned or declared) up to but excluding the date of payment, before any payment is made to holders of the common stock and any other class or series of stock ranking junior to the series I preferred stock as to liquidation rights. The rights of holders of series I preferred stock to receive their liquidation preference will be subject to the proportionate rights of any other class or series of the company’s stock ranking on parity with the series I preferred stock as to liquidation.

Optional Redemption

The company may not redeem the series I preferred stock prior to August 24, 2020, except in limited circumstances to preserve the company’s status as a REIT and pursuant to the special optional redemption right described below. On and after August 24, 2020, the series I preferred stock will be redeemable at the company’s option, in whole or in part at any time or from time to time, for cash at a redemption price of $25.00 per share, plus accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the redemption date. However, unless full cumulative dividends on the series I preferred stock for all past dividend periods have been, or contemporaneously are, paid or an amount in cash sufficient for the payment thereof is set apart by the company, no shares of series I preferred stock may be redeemed unless all outstanding shares of series I preferred stock are simultaneously redeemed; provided, that the foregoing restriction does not prevent the company from taking action necessary to preserve the company’s status as a REIT. Any partial redemption will be on a pro rata basis.

Special Optional Redemption

Upon the occurrence of a Change of Control (as defined below), the company may, at its option, redeem the series I preferred stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date (as defined below), the company exercises any of its redemption rights relating to the series I preferred stock (whether its optional redemption right or its special optional redemption right), the holders of series I preferred stock will not have the conversion right described below.

A “Change of Control” is when, after the original issuance of the series I preferred stock, the following have occurred and are continuing:

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No Maturity, Sinking Fund or Mandatory Redemption

The series I preferred stock has no stated maturity date and the company is not required to redeem the series I preferred stock at any time. Accordingly, the series I preferred stock will remain outstanding indefinitely, unless the company decides, at its option, to exercise its redemption right or, under circumstances where the holders of the series I preferred stock have a conversion right, such holders decide to convert the series I preferred stock into the company’s common stock. The series I preferred stock is not subject to any sinking fund.

Voting Rights

Holders of series I preferred stock generally have no voting rights. However, if the company is in arrears on dividends on the series I preferred stock for six or more quarterly periods, whether or not consecutive, holders of the series I preferred stock (voting together as a class with the holders of all other classes or series of parity preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote at a special meeting called upon the written request of at least 10% of such holders or at the company’s next annual meeting and each subsequent annual meeting of stockholders for the election of two additional directors to serve on the company’s board of directors until all unpaid dividends with respect to the series I preferred stock and any other class or series of parity preferred stock have been paid or declared and a sum sufficient for the payment thereof set aside for payment. In addition, the company may not make certain material and adverse changes to the terms of the series I preferred stock without the affirmative vote of the holders of at least two-thirds of the outstanding shares of series I preferred stock and all other shares of any class or series ranking on parity with the series I preferred stock that are entitled to similar voting rights (voting together as a single class).

Conversion

Upon the occurrence of a Change of Control, each holder of series I preferred stock will have the right (unless, prior to the Change of Control Conversion Date, the company has provided or provides notice of its election to redeem the series I preferred stock) to convert some or all of the series I preferred stock held by such holder on the date the series of I preferred stock is to be converted, which we refer to as the Change of Control Conversion Date, into a number of shares of the company’s common stock per share of series I preferred stock to be converted equal to the lesser of:

subject, in each case, to provisions for the receipt of alternative consideration as described in the articles supplementary relating to the Series I preferred stock.

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The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of the company’s common stock is solely cash, the amount of cash consideration per share of the company’s common stock or (ii) if the consideration to be received in the Change of Control by holders of the company’s common stock is other than solely cash (x) the average of the closing sale prices per share of the company’s common stock (or, if no closing sale price is reported, the average of the closing bid and ask prices or, if more than one in either case, the average of the average closing bid and the average closing ask prices) for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control as reported on the principal U.S. securities exchange on which the company’s common stock is then traded, or (y) the average of the last quoted bid prices for the company’s common stock in the over-the-counter market as reported by Pink Sheets LLC or similar organization for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control, if the company’s common stock is not then listed for trading on a U.S. securities exchange.

If, prior to the Change of Control Conversion Date, the company has provided or provides a redemption notice, whether pursuant to its special optional redemption right in connection with a Change of Control or its optional redemption right, holders of series I preferred stock will not have any right to convert the series I preferred stock into shares of the company’s common stock in connection with the Change of Control and any shares of series I preferred stock selected for redemption that have been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Change of Control Conversion Date.

Except as provided above in connection with a Change of Control, the series I preferred stock is not convertible into or exchangeable for any other securities or property.

Transfer Agent and Registrar

The transfer agent and registrar for the company’s series I preferred stock is American Stock Transfer & Trust Company, LLC.

5.250% Series J Cumulative Redeemable Preferred Stock

General

The company’s board of directors and a duly authorized committee thereof approved articles supplementary, a copy of which has been previously filed with the SEC and which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part, creating the series J preferred stock as a series of the company’s preferred stock, designated as the 5.250% Series J Cumulative Redeemable Preferred Stock. The following description of the series J preferred stock is qualified in its entirety by reference to such articles supplementary and the company’s charter. The series J preferred stock is validly issued, fully paid and nonassessable.

The series J preferred stock is currently listed on the NYSE as “DLR Pr J”.

Ranking

The series J preferred stock ranks, with respect to dividend rights and rights upon the company’s liquidation, dissolution or winding-up:

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Dividend Rate and Payment Date

Holders are entitled to receive cumulative cash dividends on the series J preferred stock from and including the date of original issue, payable quarterly in arrears on or about the last calendar day of March, June, September and December of each year, at the rate of 5.250% per annum of the $25.00 liquidation preference per share (equivalent to an annual amount of $1.3125 per share). Dividends on the series J preferred stock will accrue whether or not DLR has earnings, whether or not there are funds legally available for the payment of such dividends and whether or not such dividends are authorized or declared.

Liquidation Preference

In the event of a liquidation, dissolution or winding up, holders of the series J preferred stock will have the right to receive $25.00 per share, plus accrued and unpaid dividends (whether or not earned or declared) up to but excluding the date of payment, before any payment is made to holders of the common stock and any other class or series of stock ranking junior to the series J preferred stock as to liquidation rights. The rights of holders of series J preferred stock to receive their liquidation preference will be subject to the proportionate rights of any other class or series of stock ranking on parity with the series J preferred stock as to liquidation.

Optional Redemption

The series J preferred stock may not be redeemed prior to August 7, 2022, except in limited circumstances to preserve the company’s status as a REIT and pursuant to the special optional redemption right described below. On and after August 7, 2022, the series J preferred stock will be redeemable at the company’s option, in whole or in part at any time or from time to time, for cash at a redemption price of $25.00 per share, plus accrued and unpaid dividends (whether or not authorized or declared) up to but excluding the redemption date. However, unless full cumulative dividends on the series J preferred stock for all past dividend periods have been, or contemporaneously are, paid or an amount in cash sufficient for the payment thereof is set apart, no shares of series J preferred stock may be redeemed unless all outstanding shares of series J preferred stock are simultaneously redeemed; provided, that the foregoing restriction does not prevent the company from taking action necessary to preserve its status as a REIT. Any partial redemption will be on a pro rata basis.

Special Optional Redemption

Upon the occurrence of a Change of Control, the company may, at its option, redeem the series J preferred stock, in whole or in part within 120 days after the first date on which such Change of Control occurred, by paying $25.00 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption. If, prior to the Change of Control Conversion Date (as defined below), the company exercises any of its redemption rights relating to the series J preferred stock (whether its optional redemption right or its special optional redemption right), the holders of series J preferred stock will not have the conversion right described below.

A “Change of Control” is when, after the original issuance of the series I preferred stock, the following have occurred and are continuing:

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No Maturity, Sinking Fund or Mandatory Redemption

The series J preferred stock has no stated maturity date and the company is not required to redeem the series J preferred stock at any time. Accordingly, the series J preferred stock will remain outstanding indefinitely, unless the company decides, at its option, to exercise its redemption right or, under circumstances where the holders of the series J preferred stock have a conversion right, such holders decide to convert the series J preferred stock into common stock. The series J preferred stock is not subject to any sinking fund.

Voting Rights

Holders of series J preferred stock generally have no voting rights. However, if the company is in arrears on dividends on the series J preferred stock for six or more quarterly periods, whether or not consecutive, holders of the series J preferred stock (voting together as a class with the holders of all other classes or series of parity preferred stock upon which like voting rights have been conferred and are exercisable) will be entitled to vote at a special meeting called upon the written request of at least 10% of such holders or at the next annual meeting of stockholders and each subsequent annual meeting of stockholders for the election of two additional directors to serve on the company’s board of directors until all unpaid dividends with respect to the series J preferred stock and any other class or series of parity preferred stock have been paid or declared and a sum sufficient for the payment thereof set aside for payment. In addition, the company may not make certain material and adverse changes to the terms of the series J preferred stock without the affirmative vote of the holders of at least two-thirds of the outstanding shares of series J preferred stock and all other shares of any class or series ranking on parity with the series J preferred stock that are entitled to similar voting rights (voting together as a single class).

Conversion

Upon the occurrence of a Change of Control, each holder of series J preferred stock will have the right (unless, prior to the Change of Control Conversion Date, the company has provided or provides notice of its election to redeem the series J preferred stock) to convert some or all of the series J preferred stock held by such holder on the date the series of J preferred stock is to be converted, which we refer to as the Change of Control Conversion Date, into a number of shares of common stock per share of series J preferred stock to be converted equal to the lesser of:

subject, in each case, to provisions for the receipt of alternative consideration as described in the articles supplementary relating to the Series J preferred stock.

The “Common Stock Price” will be (i) if the consideration to be received in the Change of Control by the holders of common stock is solely cash, the amount of cash consideration per share of common stock or (ii) if the consideration to be received in the Change of Control by holders of common stock is other than solely cash (x) the average of the closing sale prices per share of the common stock (or, if no closing sale price is reported,

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the average of the closing bid and ask prices or, if more than one in either case, the average of the average closing bid and the average closing ask prices) for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control as reported on the principal U.S. securities exchange on which the common stock is then traded, or (y) the average of the last quoted bid prices for the DLR’s common stock in the over-the-counter market as reported by Pink Sheets LLC or similar organization for the ten consecutive trading days immediately preceding, but not including, the effective date of the Change of Control, if the common stock is not then listed for trading on a U.S. securities exchange.

If, prior to the Change of Control Conversion Date, the company has provided or provides a redemption notice, whether pursuant to its special optional redemption right in connection with a Change of Control or its optional redemption right, holders of series J preferred stock will not have any right to convert the series J preferred stock into shares of the company’s common stock in connection with the Change of Control and any shares of series J preferred stock selected for redemption that have been tendered for conversion will be redeemed on the related date of redemption instead of converted on the Change of Control Conversion Date.

Except as provided above in connection with a Change of Control, the series J preferred stock is not convertible into or exchangeable for any other securities or property.

Transfer Agent and Registrar

The transfer agent and registrar for the series J preferred stock is American Stock Transfer & Trust Company, LLC.

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DESCRIPTION OF DEPOSITARY SHARES

The company may, at its option, elect to offer depositary shares rather than full shares of preferred stock. Each depositary share will represent ownership of and entitlement to all rights and preferences of a fraction of a share of preferred stock of a specified series (including dividend, voting, redemption and liquidation rights). The applicable fraction will be specified in a prospectus supplement. The shares of preferred stock represented by the depositary shares will be deposited with a depositary named in the applicable prospectus supplement, under a deposit agreement, among the company, the depositary and the holders of the certificates evidencing depositary shares, or depositary receipts. Depositary receipts will be delivered to those persons purchasing depositary shares in the offering. The depositary will be the transfer agent, registrar and dividend disbursing agent for the depositary shares. Holders of depositary receipts agree to be bound by the deposit agreement, which requires holders to take certain actions such as filing proof of residence and paying certain charges.

The summary of the terms of the depositary shares contained in this prospectus shall apply unless otherwise specified on a supplement to this prospectus. This summary, as modified by any supplement to this prospectus, does not purport to be complete and is subject to, and qualified in its entirety by, the provisions of the deposit agreement, the company’s charter and the form of articles supplementary for the applicable series of preferred stock.

Dividends

The depositary will distribute all cash dividends or other cash distributions received in respect of the series of preferred stock represented by the depositary shares to the record holders of depositary receipts in proportion to the number of depositary shares owned by such holders on the relevant record date, which will be the same date as the record date fixed by the company for the applicable series of preferred stock. The depositary, however, will distribute only such amount as can be distributed without attributing to any depositary share a fraction of one cent, and any balance not so distributed will be added to and treated as part of the next sum received by the depositary for distribution to record holders of depositary receipts then outstanding.

In the event of a distribution other than in cash, the depositary will distribute property received by it to the record holders of depositary receipts entitled thereto, in proportion, as nearly as may be practicable, to the number of depositary shares owned by such holders on the relevant record date, unless the depositary determines (after consultation with the company) that it is not feasible to make such distribution, in which case the depositary may (with the company’s approval) adopt any other method for such distribution as it deems equitable and appropriate, including the sale of such property (at such place or places and upon such terms as it may deem equitable and appropriate) and distribution of the net proceeds from such sale to such holders.

Liquidation Preference

In the event of the liquidation, dissolution or winding up of the affairs of the company, whether voluntary or involuntary, the holders of each depositary share will be entitled to the fraction of the liquidation preference accorded each share of the applicable series of preferred stock as set forth in the applicable prospectus supplement.

Redemption

If the series of preferred stock represented by the applicable series of depositary shares is redeemable, such depositary shares will be redeemed from the proceeds received by the depositary resulting from the redemption, in whole or in part, of preferred stock held by the depositary. Whenever the company redeems any preferred stock held by the depositary, the depositary will redeem as of the same redemption date the number of depositary shares representing the preferred stock so redeemed. The depositary will mail the notice of redemption promptly upon receipt of such notice from the company and not less than 30 nor more than 60 days prior to the date fixed for redemption of the preferred stock and the depositary shares to the record holders of the depositary receipts.

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Voting

Promptly upon receipt of notice of any meeting at which the holders of the series of preferred stock represented by the applicable series of depositary shares are entitled to vote, the depositary will mail the information contained in such notice of meeting to the record holders of the depositary receipts as of the record date for such meeting. Each such record holder of depositary receipts will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the number of shares of preferred stock represented by such record holder’s depositary shares. The depositary will endeavor, insofar as practicable, to vote such preferred stock represented by such depositary shares in accordance with such instructions, and the company will agree to take all action which may be deemed necessary by the depositary in order to enable the depositary to do so. The depositary will abstain from voting any of the preferred stock to the extent that it does not receive specific instructions from the holders of depositary receipts.

Withdrawal of Preferred Stock

Upon surrender of depositary receipts at the principal office of the depositary and payment of any unpaid amount due the depositary, and subject to the terms of the deposit agreement, the owner of the depositary shares evidenced thereby is entitled to delivery of the number of whole shares of preferred stock and all money and other property, if any, represented by such depositary shares. Partial shares of preferred stock will not be issued. If the depositary receipts delivered by the holder evidence a number of depositary shares in excess of the number of depositary shares representing the number of whole shares of preferred stock to be withdrawn, the depositary will deliver to such holder at the same time a new depositary receipt evidencing such excess number of depositary shares. Holders of preferred stock thus withdrawn will not thereafter be entitled to deposit such shares under the deposit agreement or to receive depositary receipts evidencing depositary shares therefor.

Amendment and Termination of Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time and from time to time be amended by agreement between the company and the depositary. However, any amendment which materially and adversely alters the rights of the holders (other than any change in fees) of depositary shares will not be effective unless such amendment has been approved by at least a majority of the depositary shares then outstanding. No such amendment may impair the right, subject to the terms of the deposit agreement, of any owner of any depositary shares to surrender the depositary receipt evidencing such depositary shares with instructions to the depositary to deliver to the holder the preferred stock and all money and other property, if any, represented thereby, except in order to comply with mandatory provisions of applicable law.

The deposit agreement will be permitted to be terminated by the company upon not less than 30 days prior written notice to the applicable depositary if (i) such termination is necessary to preserve the company’s status as a REIT or (ii) a majority of each series of preferred stock affected by such termination consents to such termination, whereupon such depositary will be required to deliver or make available to each holder of depositary receipts, upon surrender of the depositary receipts held by such holder, such number of whole or fractional shares of preferred stock as are represented by the depositary shares evidenced by such depositary receipts together with any other property held by such depositary with respect to such depositary receipts. The company will agree that if the deposit agreement is terminated to preserve the company’s status as a REIT, then it will use its best efforts to list the preferred stock issued upon surrender of the related depositary shares on a national securities exchange. In addition, the deposit agreement will automatically terminate if (i) all outstanding depositary shares thereunder shall have been redeemed, (ii) there shall have been a final distribution in respect of the related preferred stock in connection with any liquidation, dissolution or winding-up of the company and such distribution shall have been distributed to the holders of depositary receipts evidencing the depositary shares representing such preferred stock or (iii) each share of the related preferred stock shall have been converted into stock of the company not so represented by depositary shares.

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Charges of Depositary

The company will pay all transfer and other taxes and governmental charges arising solely from the existence of the depositary arrangements. The company will pay charges of the depositary in connection with the initial deposit of the preferred stock and initial issuance of the depositary shares, and redemption of the preferred stock and all withdrawals of preferred stock by owners of depositary shares. Holders of depositary receipts will pay transfer, income and other taxes and governmental charges and certain other charges as are provided in the deposit agreement to be for their accounts. In certain circumstances, the depositary may refuse to transfer depositary shares, may withhold dividends and distributions and sell the depositary shares evidenced by such depositary receipt if such charges are not paid. The applicable prospectus supplement will include information with respect to fees and charges, if any, in connection with the deposit or substitution of the underlying securities, the receipt and distribution of dividends, the sale or exercise of rights, the withdrawal of the underlying security, and the transferring, splitting or grouping of receipts. The applicable prospectus supplement will also include information with respect to the right to collect the fees and charges, if any, against dividends received and deposited securities.

Miscellaneous

The depositary will forward to the holders of depositary receipts all notices, reports and proxy soliciting material from the company which are delivered to the depositary and which the company is required to furnish to the holders of the preferred stock. In addition, the depositary will make available for inspection by holders of depositary receipts at the principal office of the depositary, and at such other places as it may from time to time deem advisable, any notices, reports and proxy soliciting material received from the company which are received by the depositary as the holder of preferred stock. The applicable prospectus supplement will include information about the rights, if any, of holders of receipts to inspect the transfer books of the depositary and the list of holders of receipts.

Neither the depositary nor the company assumes any obligation or will be subject to any liability under the deposit agreement to holders of depositary receipts other than for its negligence or willful misconduct. Neither the depositary nor the company will be liable if it is prevented or delayed by law or any circumstance beyond its control in performing its obligations under the deposit agreement. The obligations of the company and the depositary under the deposit agreement will be limited to performance in good faith of their duties thereunder, and they will not be obligated to prosecute or defend any legal proceeding in respect of any depositary shares or preferred stock unless satisfactory indemnity is furnished. The company and the depositary may rely on written advice of counsel or accountants, on information provided by holders of the depositary receipts or other persons believed in good faith to be competent to give such information and on documents believed to be genuine and to have been signed or presented by the proper party or parties.

In the event the depositary shall receive conflicting claims, requests or instructions from any holders of depositary receipts, on the one hand, and the company, on the other hand, the depositary shall be entitled to act on such claims, requests or instructions received from the company.

Resignation and Removal of Depositary

The depositary may resign at any time by delivering to us notice of its election to do so, and the company may at any time remove the depositary, any such resignation or removal to take effect upon the appointment of a successor depositary and its acceptance of such appointment. Such successor depositary must be appointed within 60 days after delivery of the notice for resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $150,000,000.

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DESCRIPTION OF WARRANTS

The company may issue warrants for the purchase of the common stock, preferred stock or depositary shares of Digital Realty Trust, Inc., and may issue warrants independently or together with common stock, preferred stock, depositary shares or debt securities or attached to or separate from such securities. The company will issue each series of warrants under a separate warrant agreement, and may appoint a bank or trust company as warrant agent, all as specified in the applicable prospectus supplement. Any warrant agent will act solely as the company’s agent in connection with the warrants and will not act for or on behalf of warrant holders.

The following sets forth certain general terms and provisions of the warrants that may be offered under this registration statement. Further terms of the warrants and applicable warrant agreements will be set forth in the applicable prospectus supplement.

The applicable prospectus supplement will describe the terms of the warrants in respect of which this prospectus is being delivered, including, where applicable, the following:

Warrant certificates will be exchangeable for new warrant certificates of different denominations and warrants may be exercised at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement. Prior to the exercise of their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise or to any dividend payments or voting rights, as applicable, as to which holders of the shares of the common stock or preferred stock purchasable upon such exercise may be entitled.

Each warrant will entitle the holder to purchase for cash such number of shares of common stock, shares of preferred stock, or depository shares, at such exercise price as shall, in each case, be set forth, or be determinable as set forth, in the applicable prospectus supplement relating to the warrants offered thereby. Unless otherwise specified in the applicable prospectus supplement, warrants may be exercised at any time up to 5:00 p.m. New York City time on the expiration date set forth in applicable prospectus supplement. After 5:00 p.m. New York City time on the expiration date, unexercised warrants will be void.

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Warrants may be exercised as set forth in the applicable prospectus supplement relating to the warrants. Upon receipt of payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, the company will, as soon as practicable, forward the securities purchasable upon such exercise. If less than all of the warrants are presented by such warrant certificate of exercise, a new warrant certificate will be issued for the remaining amount of warrants.

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DESCRIPTION OF DEBT SECURITIES AND RELATED GUARANTEES

The following is a description of the general terms and provisions of our operating partnership’s debt securities and related guarantees by Digital Realty Trust, Inc., if applicable. When our operating partnership offers to sell a particular series of debt securities, we will describe the specific terms of the series in a supplement to this prospectus, including the terms of any related guarantees by Digital Realty Trust, Inc. and the terms, if any, on which a series of debt securities may be convertible into or exchangeable for other securities. We will also indicate in the prospectus supplement whether the general terms and provisions described in this prospectus apply to a particular series of debt securities. To the extent the information contained in the prospectus supplement differs from this summary description, you should rely on the information in the prospectus supplement.

The debt securities may be offered in the form of either senior debt securities or subordinated debt securities. Unless otherwise specified in a prospectus supplement, the debt securities will be the direct, unsecured obligations of Digital Realty Trust, L.P., and will rank equally in right of payment with all of Digital Realty Trust, L.P.’s other unsecured and unsubordinated indebtedness. The debt securities that are sold may be exchangeable for and/or convertible into common stock or any of the other securities that may be sold under this prospectus.

Unless otherwise specified in a prospectus supplement, the debt securities will be issued under an indenture between us and Wells Fargo Bank, National Association, as trustee, or the trustee. We have summarized select portions of the indenture below. The summary is not complete. We have filed the indenture as an exhibit to the registration statement of which this prospectus is a part, and you should read the indenture and our debt securities carefully for provisions that may be important to you. Capitalized terms used in the summary and not defined in this prospectus have the meaning specified in the indenture.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of the company’s board of directors and set forth or determined in the manner provided in an officer’s certificate or by a supplemental indenture. The particular terms of each series of debt securities will be described in a prospectus supplement relating to such series, including any pricing supplement.

Unless otherwise specified in a prospectus supplement, the indenture will designate Wells Fargo Bank, National Association as the trustee for the indenture with respect to one or more series of our operating partnership’s debt securities and related guarantees of our company, if applicable. Wells Fargo Bank, National Association, or any other specified trustee, may resign or be removed with respect to one or more series of our debt securities, and a successor trustee may be appointed to act with respect to that series.

Unless otherwise specified in a supplement to this prospectus, the debt securities will be our operating partnership’s direct, unsecured obligations and will rank equally with all of its other unsecured and unsubordinated indebtedness, and may be fully and unconditionally guaranteed by the company. We can issue an unlimited amount of our operating partnership’s debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. We will set forth in a prospectus supplement, including any pricing supplement, relating to any series of debt securities being offered, the aggregate principal amount and the following terms of such series of debt securities, to the extent applicable:

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In addition, the indenture does not limit our operating partnership’s ability to issue convertible or subordinated debt securities. Any conversion or subordination provisions of a particular series of debt securities will be set forth in the officer’s certificate or supplemental indenture related to that series of debt securities and will be described in the relevant prospectus supplement. Such terms may include provisions for conversion, either mandatory, at the option of the holder or at our option, in which case the number of shares of common stock, cash or other securities to be received by the holders of debt securities would be calculated as of a time and in the manner stated in the prospectus supplement.

We may issue debt securities of our operating partnership that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the other special considerations applicable to any such debt securities in the applicable prospectus supplement.

If we denominate the purchase price of any of our operating partnership’s debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of and premium, if any, and interest, if any, on any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company, as depositary, or a nominee (we will refer to any debt security represented by a

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global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities

You may transfer or exchange certificated debt securities at any office we designate for this purpose in accordance with the terms of the indenture. No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange.

You may effect the transfer of certificated debt securities and the right to receive the principal of, and premium and interest on, certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holder or the issuance by us or the trustee of a new certificate to the new holder.

Global Debt Securities and Book-Entry System

Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the depositary, and registered in the name of the depositary or a nominee of the depositary.

We will require the depositary to agree to follow the following procedures with respect to book-entry debt securities.

Ownership of beneficial interests in book-entry debt securities will be limited to persons who have accounts with the depositary for the related global debt security, which we refer to as participants, or persons who may hold interests through participants. Upon the issuance of a global debt security, the depositary will credit, on its book-entry registration and transfer system, the participants’ accounts with the respective principal amounts of the book-entry debt securities represented by such global debt security beneficially owned by such participants. The accounts to be credited will be designated by any dealers, underwriters or agents participating in the distribution of the book-entry debt securities. Ownership of book-entry debt securities will be shown on, and the transfer of such ownership interests will be effected only through, records maintained by the depositary for the related global debt security (with respect to interests of participants) and on the records of participants (with respect to interests of persons holding through participants). The laws of some states may require that certain purchasers of securities take physical delivery of such securities in definitive form. These laws may impair the ability to own, transfer or pledge beneficial interests in book-entry debt securities.

So long as the depositary for a global debt security, or its nominee, is the registered owner of that global debt security, the depositary or its nominee, as the case may be, will be considered the sole owner or holder of the book-entry debt securities represented by such global debt security for all purposes under the indenture. Except as described below, beneficial owners of book-entry debt securities will not be entitled to have securities registered in their names, will not receive or be entitled to receive physical delivery of a certificate in definitive form representing securities and will not be considered the owners or holders of those securities under the indenture. Accordingly, each person beneficially owning book-entry debt securities must rely on the procedures of the depositary for the related global debt security and, if such person is not a participant, on the procedures of the participant through which such person owns its interest, to exercise any rights of a holder under the indenture.

We understand, however, that under existing industry practice, the depositary will authorize the persons on whose behalf it holds a global debt security to exercise certain rights of holders of debt securities, and the indenture provides that we, the trustee and our respective agents will treat as the holder of a debt security the persons specified in a written statement of the depositary with respect to that global debt security for purposes of obtaining any consents or directions required to be given by holders of the debt securities pursuant to the indenture.

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We will make payments of principal of, and premium and interest on, book-entry debt securities to the depositary or its nominee, as the case may be, as the registered holder of the related global debt security. We, the trustee and any other agent of ours or agent of the trustee will not have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in a global debt security or for maintaining, supervising or reviewing any records relating to beneficial ownership interests.

We expect that the depositary, upon receipt of any payment of principal of, and premium or interest on, a global debt security, will immediately credit participants’ accounts with payments in amounts proportionate to the respective amounts of book-entry debt securities held by each participant as shown on the records of such depositary. We also expect that payments by participants to owners of beneficial interests in book-entry debt securities held through those participants will be governed by standing customer instructions and customary practices, as is now the case with the securities held for the accounts of customers registered in “street name,” and will be the responsibility of those participants.

We will issue certificated debt securities in exchange for each global debt security if the depositary is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Exchange Act and a successor depositary registered as a clearing agency under the Exchange Act is not appointed by us within 90 days. In addition, we may at any time and in our sole discretion determine not to have the book-entry debt securities of any series represented by one or more global debt securities and, in that event, will issue certificated debt securities in exchange for the global debt securities of that series. Any certificated debt securities issued in exchange for a global debt security will be registered in such name or names as the depositary shall instruct the trustee. We expect that such instructions will be based upon directions received by the depositary from participants with respect to ownership of book-entry debt securities relating to such global debt security.

We have obtained the foregoing information concerning the depositary and the depositary’s book-entry system from sources we believe to be reliable, but we take no responsibility for the accuracy of this information.

No Protection in the Event of a Change of Control

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions that may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) that could adversely affect holders of debt securities.

Covenants

We will set forth in the applicable prospectus supplement any restrictive covenants applicable to any issue of debt securities.

Consolidation, Merger and Sale of Assets

Digital Realty Trust, L.P. and Digital Realty Trust, Inc. may consolidate with, or sell, lease or convey all or substantially all of their respective assets to, or merge with or into, any other entity, provided that the following conditions are met:

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Events of Default

Event of default means, with respect to any series of debt securities, any of the following:

No event of default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an event of default with respect to any other series of debt securities. The occurrence of an event of default may constitute an event of default under our bank credit agreements in existence from time to time. In addition, the occurrence of certain events of default or an acceleration under the indenture may constitute an event of default under certain of our other indebtedness outstanding from time to time.

If an event of default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than 25% of the principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) of, and accrued and unpaid interest, if any, on all debt securities of that series. In the case of an event of default resulting from certain events of bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid interest, if any, on all outstanding debt securities will become and be immediately due and payable without any declaration or other act on the part of the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series may rescind and annul the acceleration if all events of default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. We refer you to the prospectus supplement relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of such discount securities upon the occurrence of an event of default.

The indenture provides that the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request of any holder of outstanding debt securities, unless the trustee receives indemnity

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satisfactory to it against any loss, liability or expense. Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series.

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

Notwithstanding the foregoing, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment.

The indenture requires us, within 120 days after the end of our fiscal year, to furnish to the trustee a statement as to compliance with the indenture. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any default or event of default (except in payment on any debt securities of that series) with respect to debt securities of that series if it in good faith determines that withholding notice is in the interest of the holders of those debt securities.

Modification and Waiver

We may modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We may not make any modification or amendment without the consent of the holders of each affected debt security then outstanding if that amendment will:

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Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all debt securities of that series waive our compliance with provisions of the indenture. The holders of a majority in principal amount of the outstanding debt securities of any series may on behalf of the holders of all the debt securities of such series waive any past default under the indenture with respect to that series and its consequences, except a default in the payment of the principal of, or premium or any interest on, any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration.

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance

The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, we may be discharged from any and all obligations in respect of the debt securities of any series (except for certain obligations to register the transfer or exchange of debt securities of such series, to replace stolen, lost or mutilated debt securities of such series, and to maintain paying agencies and certain provisions relating to the treatment of funds held by paying agents). We will be so discharged upon the deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. dollars, foreign government obligations, that, through the payment of interest and principal in accordance with their terms, will provide money in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of those payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an opinion of counsel stating that we have received from, or there has been published by, the United States Internal Revenue Service, or IRS, a ruling or, since the date of execution of the indenture, there has been a change in the applicable U.S. federal income tax law, in either case to the effect that, and based thereon such opinion shall confirm that, the holders of the outstanding debt securities of that series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to U.S. federal income tax on the same amounts and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred.

Defeasance of Certain Covenants

The indenture provides that, unless otherwise provided by the terms of the applicable series of debt securities, upon compliance with certain conditions:

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The conditions include:

Covenant Defeasance and Events of Default

In the event we exercise our option to effect covenant defeasance with respect to any series of debt securities and the debt securities of that series are declared due and payable because of the occurrence of any event of default, the amount of money and/or U.S. government obligations or foreign government obligations on deposit with the trustee will be sufficient to pay amounts due on the debt securities of that series at the time of their stated maturity but may not be sufficient to pay amounts due on the debt securities of that series at the time of the acceleration resulting from the event of default. In such a case, we would remain liable for those payments.

“Foreign Government Obligations” means, with respect to debt securities of any series that are denominated in a currency other than U.S. dollars:

Governing Law

The indenture and the debt securities will be governed by, and construed in accordance with, the laws of the State of New York without regard to conflict of law principles that would result in the application of any law other than the law of the State of New York.

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RESTRICTIONS ON OWNERSHIP AND TRANSFER

The following summary with respect to restrictions on ownership and transfer of Digital Realty Trust, Inc.’s stock sets forth certain general terms and provisions of the company’s charter documents to which any prospectus supplement may relate. This summary does not purport to be complete and is subject to and qualified in its entirety by reference to the company’s charter documents, as amended and supplemented from time to time, including any articles supplementary relating to any issuance of preferred stock pursuant to this prospectus. Copies of the company’s existing charter documents are filed with the SEC and are incorporated by reference as exhibits to the registration statement of which this prospectus is a part. Any amendment or supplement to the company’s charter documents relating to an issuance of securities pursuant to this prospectus shall be filed with the SEC and shall be incorporated by reference as an exhibit to the applicable prospectus supplement. See “Where You Can Find More Information.”

In order for the company to qualify as a REIT under the Internal Revenue Code of 1986, as amended, or the Code, the company’s stock must be beneficially owned by 100 or more persons during at least 335 days of a taxable year of 12 months (other than the first year for which an election to be a REIT has been made) or during a proportionate part of a shorter taxable year. Also, not more than 50% of the value of the outstanding shares of stock may be owned, directly or indirectly, by five or fewer individuals (as defined in the Code to include certain entities such as qualified pension plans) during the last half of a taxable year (other than the first year for which an election to be a REIT has been made).

The company’s charter contains restrictions on the ownership and transfer of the common stock, preferred stock and capital stock that are intended to assist the company in complying with these requirements and continuing to qualify as a REIT. The relevant sections of the company’s charter provide that, subject to the exceptions described below, no person or entity may beneficially own, or be deemed to own by virtue of the applicable constructive ownership provisions of the Code, more than 9.8% (by value or by number of shares, whichever is more restrictive) of the outstanding shares of the common stock or of any series of preferred stock, or more than 9.8% of the value of the company’s outstanding capital stock. The company refers to these restrictions as the “common stock ownership limit,” the “preferred stock ownership limit” and the “aggregate stock ownership limit,” respectively. A person or entity that becomes subject to one of the ownership limits by virtue of a violative transfer that results in a transfer to a trust, as set forth below, is referred to as a “purported beneficial transferee” if, had the violative transfer been effective, the person or entity would have been a record owner and beneficial owner or solely a beneficial owner of the common stock, any series of the company’s preferred stock, or the company’s capital stock, as applicable, or is referred to as a “purported record transferee” if, had the violative transfer been effective, the person or entity would have been solely a record owner of the common stock, any series of the company’s preferred stock, or the company’s capital stock, as applicable.

The constructive ownership rules under the Code are complex and may cause stock owned actually or constructively by a group of related individuals and/or entities to be owned constructively by one individual or entity. As a result, the acquisition of less than 9.8% of the common stock or any series of the company’s preferred stock or less than 9.8% of the value of the company’s outstanding capital stock (or the acquisition of an interest in an entity that owns, actually or constructively, the company’s capital stock) by an individual or entity could, nevertheless, cause that individual or entity, or another individual or entity, to own constructively more than 9.8% of the company’s outstanding common stock or a series of the company’s preferred stock or capital stock, as applicable, and thereby subject such stock to the applicable ownership limit.

The company’s board of directors may, in its sole discretion waive, prospectively or retroactively, the common stock ownership limit or aggregate stock ownership limit with respect to a particular stockholder if it:

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The company’s board of directors may also, in its sole discretion waive, prospectively or retroactively, the preferred stock ownership limit with respect to a particular stockholder if it determines that such waiver will not: (1) cause any individual’s beneficial ownership of shares of the company’s capital stock to violate the aggregate stock ownership limit, or (2) jeopardize the company’s status as a REIT.

As a condition of the company’s waiver, the company’s board of directors may require an opinion of counsel or IRS ruling satisfactory to the company’s board of directors, and/or representations or undertakings from the applicant with respect to preserving the company’s REIT status.

In connection with a waiver of an ownership limit or at any other time, the company’s board of directors may increase the applicable ownership limit for one or more persons and decrease the applicable ownership limit for all other persons and entities; provided, however, that the decreased ownership limit will not be effective for any person or entity whose percentage ownership in the common stock, any series of the company’s preferred stock or capital stock, as applicable, exceeds the decreased ownership limit until such time as such person or entity’s percentage ownership equals or falls below the decreased ownership limit; but any further acquisition of the company’s common, preferred or capital stock, as applicable, in excess of such percentage ownership will be in violation of the applicable ownership limit. Additionally, the new ownership limit, as applicable, may not allow five or fewer stockholders to beneficially own more than 49% in value of the company’s outstanding capital stock.

The company’s charter further prohibits:

Any person who acquires or attempts or intends to acquire beneficial or constructive ownership of shares of the company’s stock that will or may violate any of the foregoing restrictions on transferability and ownership will be required to give notice immediately to the company and provide the company with such other information as it may request in order to determine the effect of such transfer on the company’s status as a REIT. The foregoing provisions on transferability and ownership will not apply if the company’s board of directors determines that it is no longer in the company’s best interests to attempt to qualify, or to continue to qualify, as a REIT.

Pursuant to the company’s charter, if any purported transfer of the company’s stock or any other event would otherwise result in any person violating the ownership limits or such other limit as established by the company’s board of directors or would result in the company being “closely held” under Section 856(h) of the Code or otherwise failing to qualify as a REIT, then that number of shares in excess of the applicable ownership limit or causing us to be “closely held” or otherwise to fail to qualify as a REIT (rounded up to the nearest whole share) will be automatically transferred to, and held by, a trust for the exclusive benefit of one or more charitable organizations selected by the company and the intended transferee will acquire no rights in such shares. The automatic transfer will be effective as of the close of business on the business day prior to the date of the violative transfer or other event that results in the transfer to the trust. Any dividend or other distribution paid to

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the purported record transferee that are owed by the purported record transferee to the trust as described above, must be repaid to the trustee upon demand for distribution to the beneficiary of the trust, and the trustee may reduce the amount payable to the purported record transferee upon the sale of the shares transferred to the trustee (as described below) by the amount of any such dividends or other distributions which have not been repaid to the trustee. If the transfer to the trust as described above is not automatically effective, for any reason, to prevent a violation of the applicable ownership limit or the company’s being “closely held” or otherwise failing to qualify as a REIT, then the company’s charter provides that the transfer of the shares in excess of the ownership limit will be void. If any transfer would result in shares of the company’s stock being beneficially owned by fewer than 100 persons, then any such purported transfer will be void and of no force or effect and the intended transferee will acquire no rights in the shares.

Shares of the company’s stock transferred to the trustee are deemed offered for sale to the company, or the company’s designee, at a price per share equal to the lesser of (1) the price paid by the purported record transferee for the shares (or, if the event which resulted in the transfer to the trust did not involve a purchase of such shares of the company’s stock at market price, the last sales price reported on the NYSE on the trading day immediately preceding the day of the event which resulted in the transfer of such shares of the company’s stock to the trust) and (2) the market price on the date the company, or its designee, accepts such offer. The company may reduce the amount payable to the purported record transferee by the amount of dividends and distributions which have been paid to the purported record transferee and are owed by the purported record transferee to the trustee. The company will pay the amount of such reduction to the trustee for the benefit of the charitable beneficiary. The company has the right to accept such offer until the trustee has sold the shares of the company’s stock held in the trust pursuant to the clauses discussed below. Upon a sale to the company, the interest of the charitable beneficiary in the shares sold terminates and the trustee must distribute the net proceeds of the sale to the purported record transferee and any dividends or other distributions held by the trustee with respect to such stock will be paid to the charitable beneficiary.

If the company does not buy the shares, the trustee must, within 20 days of receiving notice from the company of the transfer of shares to the trust, sell the shares to a person or entity designated by the trustee who could own the shares without violating the common stock ownership limit or the preferred stock ownership limit, as applicable, and the aggregate stock ownership limit or such other limit as established by the company’s board of directors. After that, the trustee must distribute to the purported record transferee an amount equal to the lesser of (1) the price paid by the purported record transferee or owner for the shares (or, if the event which resulted in the transfer to the trust did not involve a purchase of such shares at market price, the last sales price reported on the NYSE on the trading day immediately preceding the day of the event which resulted in the transfer of such shares of the company’s stock to the trust) and (2) the sales proceeds (net of commissions and other expenses of sale) received by the trustee for the shares. The trustee may reduce the amount payable to the purported record transferee by the amount of dividends and distributions which have been paid to the purported record transferee and are owed by the purported record transferee to the trustee. Any net sales proceeds in excess of the amount payable to the purported record transferee will be immediately paid to the charitable beneficiary, together with any dividends or other distributions thereon. In addition, if prior to discovery by the company that shares of the company’s stock have been transferred to a trust, such shares of stock are sold by a purported record transferee, then such shares shall be deemed to have been sold on behalf of the trust and to the extent that the purported record transferee received an amount for or in respect of such shares that exceeds the amount that such purported record transferee was entitled to receive, such excess amount shall be paid to the trustee upon demand. The purported beneficial transferee or purported record transferee has no rights in the shares held by the trustee.

The trustee will be designated by the company and will be unaffiliated with the company and with any purported record transferee or purported beneficial transferee. Prior to the sale of any shares in excess of the common stock ownership limit, the preferred stock ownership limit or the aggregate stock ownership limit by the trust, the trustee will receive, in trust for the beneficiary, all dividends and other distributions paid by the company with respect to the shares in excess of the applicable ownership limit, and may also exercise all voting rights with respect to such shares.

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Subject to Maryland law, effective as of the date that the shares have been transferred to the trust, the trustee will have the authority, at the trustee’s sole discretion:

However, if the company has already taken irreversible corporate action, then the trustee may not rescind and recast the vote.

In addition, if the company’s board of directors or other permitted designees determine in good faith that a proposed transfer would violate the restrictions on ownership and transfer of the company’s stock set forth in the company’s charter, the company’s board of directors or other permitted designees will take such action as it deems or they deem advisable to refuse to give effect to or to prevent such transfer, including, but not limited to, causing the company to redeem shares of common stock or preferred stock, refusing to give effect to the transfer on the company’s books or instituting proceedings to enjoin the transfer.

Any beneficial owner or constructive owner of shares of the company’s stock and any person or entity (including the stockholder of record) who is holding shares of the company’s stock for a beneficial owner must, on request, provide the company with a completed questionnaire containing the information regarding the ownership of such shares, as set forth in the applicable Treasury Regulations. In addition, any person or entity that is a beneficial owner or constructive owner of shares of the company’s stock and any person or entity (including the stockholder of record) who is holding shares of the company’s stock for a beneficial owner or constructive owner shall, on request, be required to disclose to the company in writing such information as the company may request in order to determine the effect, if any, of such stockholder’s actual and constructive ownership of shares of the company’s stock on the company’s status as a REIT and to ensure compliance with the common stock ownership limit, the preferred stock ownership limit and the aggregate stock ownership limit, or as otherwise permitted by the company’s board of directors.

All certificates representing shares of the company’s common stock and preferred stock bear a legend referring to the restrictions described above.

These restrictions on ownership and transfer could delay, defer or prevent a transaction or a change of control of the company that might involve a premium price for the company’s stock or otherwise be in the best interest of the company’s stockholders.

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DESCRIPTION OF THE PARTNERSHIP AGREEMENT OF DIGITAL REALTY TRUST, L.P.

The following is only a summary of certain terms and provisions of the Sixteenth Amended and Restated Agreement of Limited Partnership of Digital Realty Trust, L.P., as amended, which we refer to as the partnership agreement, and is subject to, and qualified in its entirety by, the partnership agreement, a copy of which is filed as an exhibit to the registration statement of which this prospectus is a part.

Voting Rights

Under the partnership agreement, Digital Realty Trust, Inc., as the operating partnership’s sole general partner, exercises exclusive and complete responsibility and discretion in the operating partnership’s day-to-day management and control, can cause the operating partnership to enter into major transactions including acquisitions, dispositions and refinancings, subject to certain limited exceptions, and may not be removed as general partner by the limited partners. The limited partners do not have voting rights relating to the operating partnership’s operation and management, except in connection with matters, as described more fully below, involving amendments to the partnership agreement and transfers of the general partner’s interest.

The limited partners expressly acknowledged that Digital Realty Trust, Inc., as the operating partnership’s general partner, is acting for the benefit of the operating partnership, its limited partners and Digital Realty Trust, Inc.’s stockholders collectively. Neither Digital Realty Trust, Inc. nor its board of directors is under any obligation to give priority to the separate interests of the limited partners or Digital Realty Trust, Inc.’s stockholders in deciding whether to cause the operating partnership to take or decline to take any actions. If there is a conflict between the interests of Digital Realty Trust, Inc.’s stockholders on one hand and the operating partnership’s limited partners on the other, Digital Realty Trust, Inc. will endeavor in good faith to resolve the conflict in a manner not adverse to either Digital Realty Trust, Inc.’s stockholders or the operating partnership’s limited partners; provided, however, that for so long as Digital Realty Trust, Inc. owns a controlling interest in the operating partnership, any conflict that cannot be resolved in a manner not adverse to either Digital Realty Trust, Inc.’s stockholders or the operating partnership’s limited partners will be resolved in favor of Digital Realty Trust, Inc.’s stockholders. Digital Realty Trust, Inc. is not liable under the partnership agreement to the operating partnership or to any partner for monetary damages for losses sustained, liabilities incurred, or benefits not derived by limited partners in connection with such decisions, provided, that it has acted in good faith.

Transferability of Interests