Filed Pursuant to Rule 424(b)(5)
Registration No. 333-223487

The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to the securities has become effective under the Securities Act of 1933, as amended. This preliminary prospectus and the accompanying prospectus are not an offer to sell the securities and are not soliciting an offer to buy the securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, dated March 7, 2018

Preliminary Prospectus Supplement

(To prospectus dated March 7, 2018)

$200,000,000

Common Stock

We are offering $200,000,000 of our common stock.

Our common stock is listed on the New York Stock Exchange (the “NYSE”) under the symbol “GWRE.” On March 6, 2018, the closing sale price for our common stock was $85.23 per share. Assuming an offering price of $85.23 per share, the last reported sale price of our common stock on the NYSE on March 6, 2018, we expect to offer 2,346,591 shares of common stock in this offering.

Concurrently with this offering of our common stock, we are offering for sale $300,000,000 aggregate principal amount of our Convertible Senior Notes due 2025 (the “notes”) (or $345,000,000 aggregate principal amount if the underwriters of that offering exercise their over-allotment option to purchase additional notes in full) in an underwritten offering pursuant to a separate prospectus supplement. The closing of this offering of shares of our common stock is not conditioned upon the closing of the concurrent offering of notes and the closing of the concurrent offering of notes is not conditioned upon the closing of this offering of shares of our common stock. This prospectus supplement is not an offer to sell or a solicitation of an offer to buy any securities being offered in the concurrent offering of notes.

Investing in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-7 of this prospectus supplement and the documents incorporated by reference herein for a discussion of certain risks that you should consider in connection with an investment in our common stock.

We have granted the underwriters the right to purchase, exercisable within a 30-day period, up to an additional $30,000,000 in shares of our common stock.

Neither the Securities and Exchange Commission 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.

Delivery of shares of our common stock will be made to investors on or about                     , 2018.

March     , 2018

TABLE OF CONTENTS

Prospectus Supplement

All references in this prospectus supplement and the accompanying prospectus to “Guidewire,” “the Company,” “we,” “us,” “our” and similar terms refer to Guidewire Software, Inc. and its subsidiaries, unless we state otherwise or the context otherwise requires.

S-i

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus, gives more general information, some of which may not apply to this offering. You should read this prospectus supplement and the accompanying prospectus, including the information incorporated by reference herein and therein and any free writing prospectus we have authorized for use in connection with this offering, in their entirety before making an investment decision.

If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information in this prospectus supplement, the accompanying prospectus, any document incorporated by reference herein or therein and any free writing prospectus we have authorized for use in connection with this offering are accurate or complete only as of their respective dates, regardless of the time of delivery of this prospectus supplement, the accompanying prospectus and any authorized free writing prospectus. Our business, financial condition, results of operations and prospects may have changed since those dates.

In this prospectus supplement, as permitted by law, we “incorporate by reference” information from other documents that we file with the Securities and Exchange Commission (the “SEC”). This means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus supplement and the accompanying prospectus and should be read with the same care. When we update the information contained in documents that have been incorporated by reference by making future filings with the SEC, the information included or incorporated by reference in this prospectus supplement is considered to be automatically updated and superseded. In other words, in case of a conflict or inconsistency between information contained in this prospectus supplement and information in the accompanying prospectus or incorporated by reference into this prospectus supplement, you should rely on the information contained in the document that was filed later. See “Incorporation of Certain Documents by Reference” in this prospectus supplement.

We are not, and the underwriters are not, making an offer to sell the securities in any jurisdiction where the offer or sale is not permitted or in which the person making such offer or solicitation is not qualified to do so or to any person to whom it is unlawful to make such offer or solicitation.

You should not consider any information included or incorporated by reference in this prospectus supplement or the accompanying prospectus to be investment, legal or tax advice. You should consult your own counsel, accountants and other advisers for legal, tax, business, financial and related advice regarding the purchase of the shares of common stock offered by this prospectus supplement.

S-ii

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying prospectus, including the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and any free writing prospectus we authorize for use in connection with this offering may contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which are subject to risks and uncertainties. These forward-looking statements include statements concerning, among other things, our business strategy (including anticipated trends and developments in, and management plans for, our business and the markets in which we operate), financial results, results of operations, revenues, gross margins, operating expenses, products, projected costs and capital expenditures, research and development programs, sales and marketing initiatives and competition. In some cases, you can identify these statements by forward-looking words, such as “will,” “may,” “might,” “should,” “could,” “estimate,” “expect,” “suggest,” “believe,” “anticipate,” “intend,” “plan” and “continue,” the negative or plural of these words and other comparable terminology. Examples of forward-looking statements include statements regarding:

Forward-looking statements are not guarantees of future performance and involve risks and uncertainties. Such forward-looking statements included or incorporated by reference in this prospectus supplement, the accompanying prospectus or any applicable free writing prospectus are based on information available to us as of the date such statements were made and our then-current expectations about future events, which are inherently subject to change and involve risks and uncertainties. You should not place undue reliance on these forward-looking statements. Actual events or results may differ materially from those expressed or implied by these statements due to various factors, including but not limited to the factors discussed under the heading “Item 1A. Risk Factors” in our Annual Report on Form 10-K for the year ended July 31, 2017 (the “2017 Form 10-K”) and our Quarterly Reports on Form 10-Q for the quarters ended October 31, 2017 and January 31, 2018 and under the heading “Risk Factors” in this prospectus supplement and the accompanying prospectus.

S-iii

We do not undertake any obligation to update any forward-looking statements included or incorporated by reference in this prospectus supplement or the accompanying prospectus or any applicable free writing prospectus, whether as a result of new information, future events, or otherwise, except as required by law. All such forward-looking statements should be read as of the time the statements were made and with the recognition that these forward-looking statements may not be complete or accurate at a later date.

S-iv

S-1

S-2

S-3

S-4

S-5

S-6

RISK FACTORS

Investing in our common stock involves a high degree of risk. In addition to the other information contained in this prospectus supplement, the accompanying prospectus and in the documents that we incorporate by reference herein and therein, you should carefully consider the risks discussed below and under the heading “Item IA. Risk Factors” in our 2017 Form 10-K and Quarterly Reports on Form 10-Q for the quarters ended October 31, 2017 and January 31, 2018 before making a decision about investing in our common stock. The risks and uncertainties discussed below and in our 2017 Form 10-K and the Quarterly Reports on Form 10-Q for the quarters ended October 31, 2017 and January 31, 2018 are not the only ones facing us. Additional risks and uncertainties not presently known to us, or that we currently see as immaterial, may also harm our business. If any of these risks occur, our business, financial condition and operating results could be harmed, the trading price of our common stock could decline and you could lose part or all of your investment.

Risks Related to Our Common Stock

We may not be able to obtain capital when desired on favorable terms, if at all, and we may not be able to obtain capital or complete acquisitions through the use of equity or without dilution to our stockholders.

We may need additional financing to execute on our current or future business strategies, including to develop new or enhance existing products and services, acquire businesses and technologies, or otherwise to respond to competitive pressures.

If we raise additional funds through the issuance of equity or convertible debt securities (including in the concurrent Convertible Notes Offering), the percentage ownership of our stockholders could be significantly diluted, and newly-issued securities may have rights, preferences or privileges senior to those of existing stockholders. If we accumulate additional funds through debt financing, a substantial portion of our operating cash flow may be dedicated to the payment of principal and interest on such indebtedness, thus limiting funds available for our business activities. We cannot assure you that additional financing will be available on terms favorable to us, or at all. If adequate funds are not available or are not available on acceptable terms, when we desire them, our ability to fund our operations, take advantage of unanticipated opportunities, develop or enhance our products and services, or otherwise respond to competitive pressures would be significantly limited. Any of these factors could harm our results of operations.

Our stock price may be volatile, which could result in securities class action litigation against us.

The market price of our common stock could be subject to wide fluctuations in response to, among other things, the risk factors described in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein, and other factors beyond our control, such as fluctuations in the valuation of companies perceived by investors to be comparable to us and research analyst coverage about our business.

Furthermore, the stock markets have experienced price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many companies. These fluctuations often have been unrelated or disproportionate to the operating performance of those companies. These broad market and industry fluctuations, as well as general economic, political and market conditions, such as recessions, interest rate changes or international currency fluctuations, have and may continue to affect the market price of our common stock.

In the past, many companies that have experienced volatility in the market price of their stock have been subject to securities class action litigation. We may become the target of this type of litigation in the future. Securities litigation against us could result in substantial costs and divert our management’s attention from other business concerns, which could seriously harm our business.

S-7

This offering is not conditioned on the consummation of any other financing, including the concurrent Convertible Notes Offering.

We intend to use the net proceeds of this offering, together with the proceeds from the concurrent Convertible Notes Offering, as described in “Use of Proceeds” herein and in the prospectus supplement that pertains to the concurrent Convertible Notes Offering. However, neither the completion of this offering nor of the concurrent Convertible Notes Offering is contingent on the completion of the other, so it is possible that this offering occurs and the Convertible Notes Offering does not occur, and vice versa. We cannot assure you that the concurrent Convertible Notes Offering will be completed on the terms described above, or at all.

Our management will have broad discretion over the use of the proceeds we receive in this offering and our concurrent Convertible Notes Offering and may not apply the proceeds in ways that increase the value of your investment.

Our management generally will have broad discretion to use the net proceeds to us from this offering and our concurrent Convertible Notes Offering, and you will be relying on the judgment of our management regarding the application of these proceeds. Our management might not apply the net proceeds from this offering and our concurrent Convertible Notes Offering in ways that increase the value of your investment. Other than the payments in respect of the capped call transactions, we have not allocated the net proceeds from this offering or our concurrent Convertible Notes Offering for any specific purposes. Until we use the net proceeds to us from this offering and our concurrent Convertible Notes Offering, we plan to invest them, and these investments may not yield a favorable rate of return. If we do not invest or apply the net proceeds from this offering or our concurrent Convertible Notes Offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

The concurrent Convertible Notes Offering and any future sales of our common stock in the public markets, or the perception that such sales might occur, could reduce the price that our common stock might otherwise attain and may dilute the voting power and ownership interest in us of our then-existing stockholders.

Concurrently with this offering of common stock, we are offering     % Convertible Senior Notes due 2025 in the aggregate principal amount of $300 million (or $345 million if the underwriters in that offering exercise in full their over-allotment option to purchase additional notes) pursuant to a separate prospectus supplement in the concurrent Convertible Notes Offering. This offering is not contingent upon the completion of the concurrent Convertible Notes Offering and the concurrent Convertible Notes Offering is not contingent upon the completion of this offering of common stock. The sale of the notes in the concurrent Convertible Notes Offering could lower the market price for our common stock.

In the future, we may sell additional shares of our common stock to raise capital. In addition, a substantial number of shares of our common stock are reserved for issuance upon conversion of the notes to be issued in our concurrent Convertible Notes Offering or our outstanding stock options, or the vesting of our outstanding restricted stock units. We cannot predict the size of future issuances or the effect, if any, that they may have on the market price for our common stock. The issuance and sale of substantial amounts of common stock, or the perception that such issuances and sales may occur, could adversely affect the trading price of our common stock and the market price of our common stock and impair our ability to raise capital through the sale of additional equity securities.

Subject to certain exceptions described under the caption “Underwriting,” we and our directors and executive officers, have agreed not to offer, sell or agree to sell, directly or indirectly, any shares of common stock without the permission of Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC and Citigroup Global Markets Inc., as representatives of the Underwriters (the “Representatives”), for a period of 90 days from the date of this prospectus supplement. When the lock-up period expires, we and our directors and executive officers will be able to sell our shares in the public market. In addition, the Representatives may release all or some portion of the

S-8

shares subject to lock-up agreements prior to expiration of the lock-up period. Sales of a substantial number of such shares upon expiration, or the perception that such sales may occur, or early release, of the lock-up could cause our share price to decline or make it more difficult for holders of our common stock to sell such common stock at a time and price that deemed appropriate. Subject to certain limitations, we also may issue our shares of common stock or securities convertible into our common stock from time to time in connection with a financing, an acquisition, investments or otherwise. Any such issuance could result in substantial dilution to our existing stockholders and cause the trading price of our common stock to decline.

We currently do not intend to pay dividends on our common stock and, consequently, your only opportunity to achieve a return on your investment in our common stock is if the price of our common stock appreciates.

We currently do not plan to declare dividends on shares of our common stock in the foreseeable future. Consequently, the only opportunity to achieve a return on investment on our common stock will be if the market price of our common stock appreciates and shares are sold at a profit.

Certain provisions of our certificate of incorporation and bylaws and of Delaware law could prevent a takeover that stockholders consider favorable and could also reduce the market price of our stock.

Our amended and restated certificate of incorporation and our amended and restated bylaws contain provisions that could delay or prevent a merger, acquisition or other change in control that stockholders may consider favorable, including transactions in which stockholders might otherwise receive a premium for their shares. These provisions may also prevent or delay attempts by stockholders to replace or remove our current management or members of our board of directors. These provisions include:

The affirmative vote of the holders of at least 66 2/3% of our shares of capital stock entitled to vote is generally necessary to amend or repeal the above provisions that are contained in our amended and restated certificate of incorporation. Also, absent approval of our board of directors, our amended and restated bylaws may only be amended or repealed by the affirmative vote of the holders of at least 50% of our shares of capital stock entitled to vote.

In addition, we are subject to the provisions of Section 203 of the Delaware General Corporation Law. These provisions may prohibit large stockholders, in particular those owning 15% or more of our outstanding common stock, from engaging in certain business combinations without approval of substantially all of our stockholders for a certain period of time.

S-9

These and other provisions in our amended and restated certificate of incorporation, our amended and restated bylaws and under Delaware law could discourage potential takeover attempts, reduce the price that investors might be willing to pay for shares of our common stock in the future and result in the market price being lower than it would be without these provisions.

Risks Related to Our Concurrent Convertible Notes Offering

The capped call transactions to be entered into in connection with the concurrent Convertible Notes Offering may affect the value of our common stock.

In connection with the pricing of the notes to be sold in the concurrent Convertible Notes Offering, we expect to enter into capped call transactions with the option counterparties. The capped call transactions are expected generally to reduce the potential dilution upon conversion of the notes and/or offset any cash payments we are required to make in excess of the principal amount of converted notes, as the case may be, with such reduction and/or offset subject to a cap. If the underwriters exercise their over-allotment option to purchase additional notes with respect to the concurrent Convertible Notes Offering, we expect to enter into additional capped call transactions with the option counterparties.

In connection with establishing their initial hedges of the capped call transactions, the option counterparties or their respective affiliates expect to enter into various derivative transactions with respect to our common stock concurrently with or shortly after the pricing of the notes in the concurrent Convertible Notes Offering. This activity could increase (or reduce the size of any decrease in) the market price of our common stock at that time.

In addition, the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding derivatives with respect to our common stock and/or purchasing or selling our common stock or other securities of ours in secondary market transactions following the pricing of the notes in the concurrent Convertible Notes Offering and prior to the maturity of the notes (and are likely to do so during any observation period related to a conversion of notes). This activity could also cause or avoid an increase or a decrease in the market price of our common stock.

In addition, if any such capped call transactions fail to become effective, whether or not the concurrent Convertible Notes Offering is completed, the option counterparties or their respective affiliates may unwind their hedge positions with respect to our common stock, which could adversely affect the value of our common stock.

Conversion of the notes will dilute the ownership interest of our existing stockholders or may otherwise depress the price of our common stock.

The conversion of some or all of the notes will dilute the ownership interests of existing stockholders. Any sales in the public market of our common stock issuable upon such conversion could adversely affect prevailing market prices of our common stock. In addition, the existence of the notes may encourage short selling by market participants because the conversion of the notes could be used to satisfy short positions, or anticipated conversion of the notes into shares of our common stock could depress the price of our common stock.

S-10

USE OF PROCEEDS

We estimate that the net proceeds from this offering of common stock will be approximately $     million, after deducting underwriting discounts and estimated offering expenses payable by us. If the underwriters’ option to purchase additional shares of our common stock in this offering is exercised in full, we estimate that the net proceeds from this offering will be approximately $             million, after deducting underwriting discounts and estimated offering expenses payable by us. In addition, concurrently with this common stock offering, we are offering     % Convertible Senior Notes due 2025 in the aggregate principal amount of $300 million (or $345 million if the underwriters of such offering exercise in full their over-allotment option to purchase additional notes) pursuant to a separate prospectus supplement in the concurrent Convertible Notes Offering. The net proceeds of the concurrent Convertible Notes Offering, after deducting underwriting discounts and commissions and estimated expenses payable by us, are expected to be approximately $             million (or approximately $             million if the underwriters in the Convertible Notes Offering exercise in full their over-allotment option to purchase additional notes).

In connection with our concurrent Convertible Notes Offering, we expect to enter into capped call transactions with one or more option counterparties, which may include some of the underwriters and/or their respective affiliates and/or other financial institutions, as described under “Underwriting—Concurrent Convertible Notes Offering; Capped Call Transactions.” We intend to use approximately $             of the net proceeds from the concurrent Convertible Notes Offering to pay the cost of the capped call transactions.

We intend to use the remaining net proceeds from this common stock offering and our concurrent Convertible Notes Offering for working capital and other general corporate purposes. The amount and timing of these expenditures will vary depending on a number of factors, including competitive and technological developments and the rate of growth, if any, of our business. In addition, we may use a portion of the net proceeds to acquire or invest in complementary companies, product lines, products or technologies. However, we have no understandings or agreements with respect to any such acquisition or investment.

Pending their use, we plan to invest the net proceeds from this offering in cash, money market funds, commercial paper, corporate bonds, U.S. agency debt securities and U.S. government bonds.

If the underwriters in the concurrent Convertible Notes Offering exercise their over-allotment option to purchase additional notes, we expect to use a portion of the net proceeds from the sale of the additional notes offered in the concurrent Convertible Notes Offering to enter into additional capped call transactions with the option counterparties and the balance of the net proceeds for working capital and other general corporate purposes.

Neither the completion of this offering nor of the concurrent Convertible Notes Offering is contingent on the completion of the other, so it is possible that this offering occurs and the concurrent Convertible Notes Offering does not occur, and vice versa. We cannot assure you that the concurrent Convertible Notes Offering will be completed on the terms described above, or at all.

S-11

PRICE RANGE OF COMMON STOCK

Our common stock is listed on the New York Stock Exchange under the symbol “GWRE.” The following table sets forth the high and low sales price per share of our common stock as reported on the NYSE for the periods indicated:

On March 6, 2018, the last reported sale price of our common stock on the NYSE was $85.23 per share. As of March 2, 2018, we had 58 holders of record of our common stock. The actual number of stockholders is greater than this number of record holders, and includes stockholders who are beneficial owners, but whose shares are held in street name by brokers and other nominees. This number of holders of record also does not include stockholders whose shares may be held in trust by other entities.

DIVIDEND POLICY

We have never declared or paid cash dividends on our common stock. We currently intend to retain all available funds and any future earnings for use in the operation of our business and do not anticipate paying any dividends on our common stock in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors and will depend on our financial condition, results of operations, capital requirements, general business conditions and other factors that our board of directors may deem relevant.

S-12

CAPITALIZATION

The following table sets forth our consolidated cash, cash equivalents and short-term investments and capitalization as of January 31, 2018:

You should read this table in conjunction with “Use of Proceeds” as well as our “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements, including the related notes, included in our Quarterly Report on Form 10-Q for the quarter ended January 31, 2018, which is incorporated by reference herein.

S-13

S-14

CONCURRENT CONVERTIBLE NOTES OFFERING

Concurrently with this offering of our common stock, we are offering $300,000,000 aggregate principal amount of     % Convertible Senior Notes due 2025 ($345,000,000 aggregate principal amount if the underwriters exercise in full their over-allotment option to purchase additional notes) pursuant to a separate prospectus supplement in an underwritten public offering. However, amounts sold in each offering may increase or decrease based on market conditions relating to a particular security. This offering is not contingent upon our concurrent Convertible Notes Offering and our concurrent Convertible Notes Offering is not contingent upon this common stock offering. We cannot assure you that our concurrent Convertible Notes Offering will be completed.

The notes will mature on March 15, 2025 unless earlier converted or repurchased. The notes will bear interest at a rate of     % per year, payable semiannually in arrears on March 15 and September 15 of each year, beginning on September 15, 2018. Subject to satisfaction of certain conditions and during certain periods, the notes may be converted at an initial conversion rate of              shares of common stock per $1,000 principal amount of notes (equivalent to an initial conversion price of approximately $         per share of common stock). The conversion rate is subject to adjustment if certain events occur.

See “Use of Proceeds” for additional information regarding the use of proceeds from our concurrent Convertible Notes Offering.

S-15

MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following is a summary of the material U.S. federal income tax considerations of the ownership and disposition of our common stock to non-U.S. holders (defined below), but does not purport to be a complete analysis of all the potential tax considerations relating thereto. This summary is based upon the provisions of the Internal Revenue Code of 1986, as amended, or the Code, Treasury regulations promulgated thereunder, administrative rulings and judicial decisions, all as of the date hereof. These authorities may be changed or subject to differing interpretations, possibly with retroactive effect, so as to result in U.S. federal income tax consequences different from those set forth below. We have not sought any ruling from the Internal Revenue Service, or the IRS, with respect to the statements made and the conclusions reached in the following summary, and there can be no assurance that the IRS will agree with such statements and conclusions.

This summary also does not address the tax considerations arising under the laws of any U.S. state or local or any non-U.S. jurisdiction, U.S. federal estate or gift tax laws, the Medicare tax on net investment income or any alternative minimum tax consequences. In addition, this discussion does not address tax considerations applicable to an investor’s particular circumstances or to investors that may be subject to special tax rules, including, without limitation:

In addition, if a partnership, including any entity or arrangement classified as a partnership for U.S. federal income tax purposes, holds our common stock, the tax treatment of a partner generally will depend on the status of the partner and upon the activities of the partnership. Accordingly, partnerships that hold our common stock, and partners in such partnerships, should consult their tax advisors.

S-16

You are urged to consult your tax advisor with respect to the application of the U.S. federal income tax laws to your particular situation, as well as any tax consequences of the purchase, ownership and disposition of our common stock arising under the U.S. federal estate or gift tax rules or under the laws of any U.S. state or local or any non-U.S. or other taxing jurisdiction or under any applicable tax treaty.

Non-U.S. Holder Defined

For purposes of this discussion, you are a non-U.S. holder if you are a beneficial owner of our common stock that is for United States federal income tax purposes (i) a foreign corporation or any other foreign organization taxable as a corporation for U.S. federal income tax purposes, (ii) a nonresident alien individual, or (iii) a foreign estate or trust that in either case is not subject to U.S. federal income tax on a net-income basis on income or gain from a note or share of common stock.

Distributions

As discussed under “Dividend Policy,” above, we do not anticipate paying any dividends on our capital stock in the foreseeable future. If we were to make distributions on our common stock, those payments will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. To the extent those distributions exceed both our current and our accumulated earnings and profits, they will constitute a return of capital and will first reduce your basis in our common stock, but not below zero, and then will be treated as gain from the sale of stock, subject to the tax treatment described in the discussion below regarding taxable dispositions of our common stock. Any such distributions would also be subject to the discussions below regarding backup withholding and FATCA.

Subject to the discussion below regarding a dividend received by you that is effectively connected with the conduct of a U.S. trade or business, a dividend paid to you generally will be subject to U.S. withholding tax either at a rate of 30% of the gross amount of the dividend or such lower rate as may be specified by an applicable income tax treaty. In order to receive a reduced treaty rate, you must provide us with an IRS Form W-8BEN (generally including a U.S. taxpayer identification number), IRS Form W-8-BEN-E or another appropriate version of IRS Form W-8 (or a successor form), in each case, certifying qualification for the reduced rate.

Dividends received by you that are effectively connected with the conduct of a U.S. trade or business (and, if required by an applicable income tax treaty, are attributable to a permanent establishment maintained by you in the United States) generally are exempt from such withholding tax. In order to obtain this exemption, you must provide us with an IRS Form W-8ECI or successor form or other applicable IRS Form W-8 properly certifying such exemption. Such effectively connected dividends, although not subject to withholding tax, are taxed at the same graduated rates applicable to U.S. persons, net of certain deductions and credits. In addition, if you are a corporate non-U.S. holder, you may also be subject to a branch profits tax at a rate of 30% or such lower rate as may be specified by an applicable income tax treaty on your earnings and profits in respect of such effectively connected dividend income.

If you are eligible for a reduced rate of withholding tax pursuant to a tax treaty, you may be able to obtain a refund of any excess amounts currently withheld if you file an appropriate claim for refund with the IRS.

Gain on Sale or Other Taxable Disposition of Common Stock

Subject to the discussion below regarding backup withholding and FATCA, a non-U.S. Holder generally will not be required to pay U.S. federal income tax on any gain realized upon the sale or other taxable disposition of our common stock unless:

S-17

Backup Withholding and Information Reporting

Generally, we must report annually to the IRS the amount of dividends paid to you, your name and address, and the amount of tax withheld, if any. A similar report will generally be sent to you. Pursuant to applicable income tax treaties or other agreements, the IRS may make these reports available to tax authorities in your country of residence.

Payments of dividends or of proceeds on the disposition of stock made to you may be subject to additional information reporting and backup withholding at the then applicable rate unless you establish an exemption, for example by properly certifying your non-U.S. status on an IRS Form W-8BEN, IRS Form W-8BEN-E or another appropriate version of IRS Form W-8 (or a successor form). Notwithstanding the foregoing, backup withholding and information reporting may apply if either we or our paying agent has actual knowledge, or reason to know, that you are a U.S. person.

Backup withholding is not an additional tax; rather, the U.S. income tax liability of persons subject to backup withholding will be reduced by the amount of tax withheld. If withholding results in an overpayment of taxes, a refund or credit may generally be obtained from the IRS, provided that the required information is furnished to the IRS in a timely manner.

Foreign Account Tax Compliance Act (“FATCA”)

Provisions commonly referred to as “FATCA” may impose withholding tax on certain types of payments made to “foreign financial institutions” and certain other non-U.S. entities. The legislation imposes a 30% withholding tax on dividends on, or gross proceeds from the sale or other disposition of, our common stock paid to a foreign financial institution or to certain non-financial foreign entities, unless (i) the foreign financial institution undertakes certain diligence and reporting obligations, (ii) the non-financial foreign entity either certifies it does not have any substantial U.S. owners or furnishes identifying information regarding each substantial U.S. owner and such entity meets certain other specified requirements, or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. If the payee is a foreign financial institution and is subject to the requirements in (i) above, it must enter into an agreement with the U.S.

S-18

Treasury requiring, among other things, that it undertake to identify accounts held by certain U.S. persons or U.S.-owned foreign entities, annually report certain information about such accounts, and withhold 30% on payments to account holders whose actions prevent it from complying with these reporting and other requirements. If the country in which a payee is resident has entered into an “intergovernmental agreement” with the United States regarding FATCA, that agreement may permit the payee to report to that country rather than to the U.S. Treasury. Under final regulations and published guidance, the obligation to withhold from payments made to a foreign financial institution or a foreign non-financial entity under the new legislation with respect to dividends on our common stock are currently in effect, but with respect to the gross proceeds of a sale or other disposition of our common stock will not begin until January 1, 2019. Prospective investors should consult their tax advisors regarding FATCA.

The preceding discussion of U.S. federal income tax considerations is for general information only. It is not tax advice. Each prospective investor should consult its own tax advisor regarding the particular U.S. federal, state and local and non-U.S. tax consequences of purchasing, holding and disposing of our common stock, including the consequences of any proposed change in applicable laws.

S-19

UNDERWRITING

We and Goldman Sachs & Co. LLC, J.P. Morgan Securities LLC and Citigroup Global Markets Inc., as representatives of the underwriters named below, intend to enter into an underwriting agreement with respect to our common stock. Subject to certain conditions, we have agreed to sell to the underwriters, and the underwriters have agreed to purchase from us, severally, the number of shares of our common stock indicated below:

Subject to the terms and conditions set forth in the underwriting agreement, the underwriters are committed to purchase all the shares of common stock offered by us in the public offering if they purchase any shares. The underwriting agreement also provides that if an underwriter defaults, the purchase commitments of nondefaulting underwriters may also be increased or the offering may be terminated. The offering of the shares by the underwriters is subject to receipt and acceptance and subject to the underwriters’ right to reject any order in whole or in part.

The underwriters propose to offer the common shares directly to the public at the public offering price set forth on the cover page of this prospectus supplement and to certain dealers at that price less a concession not in excess of $        per share. After the public offering of the shares, the offering price and other selling terms may be changed by the underwriters.

The underwriters have an option to buy up to $30,000,000 of additional shares of common stock from us, solely to cover over-allotments, if any. The underwriters have 30 days from the date of this prospectus supplement to exercise this option. If any shares are purchased with this option to purchase additional shares, the underwriters will purchase shares in approximately the same proportion as shown in the table above. If any additional shares of common stock are purchased, the underwriters will offer the additional shares on the same terms as those on which the shares are being offered. The underwriting fee for the shares sold in the public offering is equal to the public offering price per share of common stock less the amount paid by the underwriters to us per share of common stock. The underwriting fee is $        per share. The following table shows the per share and total underwriting discounts and commissions to be paid to the underwriters assuming both no exercise and full exercise of the underwriters’ option to purchase additional shares.

Paid by Us

We estimate that the total expenses of this offering, including registration, filing and listing fees, printing fees and legal and accounting expenses, but excluding the underwriting discounts and commissions, will be approximately $            .

S-20

A prospectus in electronic format may be made available on the web sites maintained by one or more underwriters, or selling group members, if any, participating in the offering. The underwriters may agree to allocate a number of shares to underwriters and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the representatives to underwriters and selling group members that may make Internet distributions on the same basis as other allocations.

No Sale of Similar Securities

We and our directors and our executive officers have agreed with the underwriters, subject to certain exceptions, not to offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of any shares of common stock, options or warrants to purchase shares of common stock or securities convertible into, exchangeable for or that represent the right to receive shares of common stock or engage in any other transaction which is designed to or which reasonably could be expected to lead to or result in a sale or disposition of shares of our common stock, during the period from the date of this prospectus supplement continuing through the date 90 days after the date of this prospectus supplement, except with the prior written consent of the representatives.

With respect to issuances or sales by us, this agreement does not apply to (i) the offer and sale of shares of common stock in this offering; (ii) the offer and sale of the notes or shares of common stock upon conversion thereof pursuant to the concurrent Convertible Notes Offering; (iii) the entry into, or the consummation of the transactions contemplated by, the capped call transactions pursuant to the concurrent Convertible Notes Offering; (iv) any securities convertible into, or exercisable for, shares of common stock issued pursuant to any employee stock option plan, incentive plan, stock plan, dividend reinvestment plan or otherwise; (v) the grant of awards pursuant to employee equity-based compensation plans, incentive plans, stock plans, or other arrangements in place at the time of this prospectus supplement; (vi) the filing of a registration statement on Form S-8 in connection with the registration of shares of common stock issuable under any employee equity-based compensation plan, incentive plan, stock plan, dividend reinvestment plan adopted and approved by the Company’s board of directors; or (vii) the issuance of shares of stock representing up to 10% of the outstanding shares of common stock as of the date hereof in connection with the acquisition of the assets of, or a majority or controlling portion of the equity of, or a joint venture with another entity in connection with its acquisition by the Company or any of its subsidiaries of such entity; provided that each recipient of any shares of common stock pledged, issued or sold pursuant to (vii) above executes and delivers to the Representatives prior to such issuance or sale (as the case may be) an agreement having substantially the same lock-up terms.

With respect to issuances or sales by our directors and executive officers, this agreement does not apply to transfers of our common stock (i) as a bona fide gift or gifts or by will or intestacy, provided that the donee or donees thereof agree to be bound in writing by the restrictions set forth above; (ii) to any trust for the direct or indirect benefit of the holder or the immediate family of the holder, or limited partnerships or limited liability companies, the partners or members of which are the holder and/or the family members of the holder, in each case, for estate planning purposes, provided that the trust, partnership or limited liability company, as applicable, agrees to be bound in writing by the restrictions set forth above and any such transfer shall not involve a disposition for value; (iii) if the holder is a corporation, limited liability company, partnership or other entity, to any members, stockholders, partners, subsidiaries or affiliates of the holder, or to any investment fund or other entity that controls or manages or is controlled or managed by the holder, provided that the distributee thereof agrees to be bound in writing by the restrictions set forth above; (iv) pursuant to domestic relations or court orders, provided that the distributee thereof agrees to be bound in writing by the restrictions set forth above; (v) (A) in connection with the vesting or settlement of restricted stock units or the “net” or “cashless” exercise of options or other rights to purchase shares of common stock for purposes of exercising such options or rights, including the payment of taxes due as a result of the vesting, settlement or exercise of such restricted stock units, options or rights, and (B) any transfer that would involve a sale of any shares of common stock in connection with such vesting, settlement, or exercise to generate the amount of cash needed to cover the applicable exercise price, tax withholdings, or remittance payments (including estimated amounts) due upon such event, in all such

S-21

cases, pursuant to equity awards granted under a stock incentive plan or other equity award plan, which plan is described in the Company’s filings with the SEC as of the date hereof; (vi) sales or transfers of shares of our common stock made pursuant to a 10b5-1 Plan that was entered into by the holder prior to the date of this prospectus supplement (an “Existing Plan”), provided that (x) if the holder reports any such sale or transfer on a Form 4 under Section 16(a) of the Exchange Act, the holder shall cause such Form 4 to include a statement that such transfer was effected pursuant to an Existing Plan that was in effect on the date of this prospectus supplement and (y) the holder shall not, without the prior written consent of the Representatives, amend any Existing Plan to permit sales or transfers of additional shares during the restricted period set forth above unless such transfer is otherwise permitted; (vii) to the Company in connection with the repurchase of shares of common stock pursuant to agreements under which the Company has the option to repurchase such shares or securities upon termination of service of the holder; (viii) pursuant to a bona fide third-party tender offer, merger, consolidation or other similar transaction made to all holders of the Company’s capital stock involving a change of control of the Company, provided that in the event that such tender offer, merger, consolidation or other such transaction is not completed, the holders’ securities shall remain subject to the restrictions set forth above; or (ix) with the prior written consent of the Representatives. In the case of each of (i), (ii) and (iii) in the foregoing sentence, no filing by any party (whether donor, done, transferor or transferee) under Section 16(a) of the Exchange Act, or other public announcement, shall be required or made voluntarily in connection with such transfer (in each case, other than a Form 5 made after the expiration of the restricted period set forth above), and in the case of each of (iv), (v) and (vii) in the foregoing sentence, if the holder reports any such transfer under Section 16(a) of the Exchange Act, the holder shall cause such report to include a statement that such transfer was effected for the purpose stated in (iv), (v) or (vii), as the case may be. For purposes of this prospectus supplement, “immediate family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

Concurrent Convertible Notes Offering; Capped Call Transactions

Concurrently with this offering, pursuant to a separate prospectus supplement, we are offering $300,000,000 aggregate principal amount of the notes (or $345,000,000 principal amount of notes if the underwriters in that offering exercise their option to purchase additional notes in full). Any such sales of the notes or any sales of our common stock issued upon conversion of the notes in the public market may affect the price of our common stock. Neither the completion of this offering nor the concurrent Convertible Notes Offering is contingent on the completion of the other, so it is possible that this offering occurs and the Convertible Notes Offering does not occur, and vice versa. We cannot assure you that the concurrent Convertible Notes Offering will be completed on the terms described above, or at all.

In connection with the pricing of the notes, we expect to enter into capped call transactions with one or more of the underwriters and/or their respective affiliates and/or other financial institutions, which we refer to as the option counterparties. The capped call transactions are expected generally to reduce the potential dilution to our common stock upon any conversion of the notes and/or offset any cash payments we are required to make in excess of the principal amount of converted notes, as the case may be, with such reduction and/or offset subject to a cap.

If the underwriters exercise their option to purchase additional notes, we expect to enter into additional capped call transactions with the option counterparties.

In connection with establishing their initial hedges of the capped call transactions, the option counterparties or their respective affiliates expect to enter into derivative transactions with respect to our common stock concurrently with or shortly after the pricing of the notes. This activity could increase (or reduce the size of any decrease in) the market price of our common stock or the notes at that time.

In addition, the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding derivatives with respect to our common stock and/or purchasing or selling our common stock

S-22

or other securities of ours in secondary market transactions following the pricing of the notes and prior to the maturity of the notes (and are likely to do so during any observation period related to a conversion of notes). This activity could also cause or avoid an increase or a decrease in the market price of our common stock.

For a discussion of the potential impact of any market or other activity by the option counterparties or their respective affiliates in connection with the capped call transactions, see “Risk Factors—Risks Related to Our Concurrent Convertible Notes Offering—The capped call transactions to be entered into in connection with the concurrent Convertible Notes Offering may affect the value of our common stock.”

Price Stabilization and Short Positions

In connection with this offering, the underwriters may engage in stabilizing transactions, which involves making bids for, purchasing and selling shares of common stock in the open market for the purpose of preventing or retarding a decline in the market price of our common stock while this offering is in progress. These stabilizing transactions may include making short sales of our common stock, which involves the sale by the underwriters of a greater number of shares of common stock than they are required to purchase in this offering, and purchasing shares of common stock on the open market to cover positions created by short sales. Short sales may be “covered” shorts, which are short positions in an amount not greater than the underwriters’ option to purchase additional shares referred to above, or may be “naked” shorts, which are short positions in excess of that amount. The underwriters may close out any covered short position either by exercising their option to purchase additional shares, in whole or in part, or by purchasing shares in the open market. In making this determination, the underwriters will consider, among other things, the price of shares available for purchase in the open market compared to the price at which the underwriters may purchase shares through the option to purchase additional shares. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of our common stock in the open market that could adversely affect investors who purchase in this offering. To the extent that the underwriters create a naked short position, they will purchase shares in the open market to cover the position.

The underwriters have advised us that, pursuant to Regulation M of the Securities Act, they may also engage in other activities that stabilize, maintain or otherwise affect the price of our common stock, including the imposition of penalty bids. This means that if the representatives of the underwriters purchase common stock in the open market in stabilizing transactions or to cover short sales, the representatives can require the underwriters that sold those shares as part of this offering to repay the underwriting discount received by them.

These activities may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock, and, as a result, the price of our common stock may be higher than the price that otherwise might exist in the open market. If the underwriters commence these activities, they may discontinue them at any time. The underwriters may carry out these transactions on The NYSE, in the over-the-counter market or otherwise.

In addition, in connection with this offering the underwriters may engage in passive market making transactions in our common stock on The NYSE prior to the pricing and completion of this offering. Passive market making consists of displaying bids on The NYSE no higher than the bid prices of independent market makers and making purchases at prices no higher than these independent bids and effected in response to order flow. Net purchases by a passive market maker on each day are generally limited to a specified percentage of the passive market maker’s average daily trading volume in our common stock during a specified period and must be discontinued when such limit is reached. Passive market making may cause the price of our common stock to be higher than the price that otherwise would exist in the open market in the absence of these transactions. If passive market making is commenced, it may be discontinued at any time.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act.

S-23

Other Relationships

The underwriters and their respective affiliates are full service financial institutions engaged in various activities, which may include sales and trading, commercial and investment banking, advisory, investment management, investment research, principal investment, hedging, market making, brokerage and other financial and non-financial activities and services. Certain of the underwriters and their respective affiliates have provided, and may in the future provide, a variety of these services to the issuer and to persons and entities with relationships with the issuer, for which they received or will receive customary fees and expenses. The underwriters are also acting as underwriters in our concurrent Convertible Notes Offering for which they will receive customary underwriting discounts and commissions and such underwriters or their affiliates may be option counterparties to our capped call transactions.

In the ordinary course of their various business activities, the underwriters and their respective affiliates, officers, directors and employees may purchase, sell or hold a broad array of investments and actively trade securities, derivatives, loans, commodities, currencies, credit default swaps and other financial instruments for their own account and for the accounts of their customers, and such investment and trading activities may involve or relate to assets, securities and/or instruments of the issuer (directly, as collateral securing other obligations or otherwise) and/or persons and entities with relationships with the issuer. The underwriters and their respective affiliates may also communicate independent investment recommendations, market color or trading ideas and/or publish or express independent research views in respect of such assets, securities or instruments and may at any time hold, or recommend to clients that they should acquire, long and/or short positions in such assets, securities and instruments.

Foreign Jurisdictions

Sales Outside of the United States

Other than in the United States, no action has been taken by us or the underwriters that would permit a public offering of the securities offered by this prospectus supplement in any jurisdiction where action for that purpose is required. The securities offered by this prospectus supplement may not be offered or sold, directly or indirectly, nor may this prospectus supplement or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus supplement comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus supplement. This prospectus supplement does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus supplement in any jurisdiction in which such an offer or a solicitation is unlawful.

European Economic Area

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a “Relative Member State”) an offer to the public of our common stock may not be made in that Relevant Member State, except that an offer to the public in that Relevant Member State of our common stock may be made at any time under the following exemptions under the Prospectus Directive:

provided that no such offer or shares of our common stock shall result in a requirement for the publication by us of a prospectus pursuant to Article 3 of the Prospectus Directive.

S-24

For the purposes of this provision, the expression an “offer to public” in relation to our common stock in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and our common stock to be offered so as to enable an investor to decide to purchase our common shares, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State, the expression “Prospectus Directive” means Directive 2003/71/EC (as amended), including by Directive 2010/73/EU and includes any relevant implementing measure in the Relevant Member State.

This European Economic Area selling restriction is in addition to any other selling restrictions set out below.

United Kingdom

In the United Kingdom, this prospectus is only addressed to and directed as qualified investors who are (i) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the Order); or (ii) high net worth entities and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”). Any investment or investment activity to which this prospectus relates is available only to relevant persons and will only be engaged with relevant persons. Any person who is not a relevant person should not act or relay on this prospectus or any of its contents.

Canada

The securities may be sold in Canada only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions, and Ongoing Registrant Obligations. Any resale of the securities must be made in accordance with an exemption form, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this offering memorandum (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

Hong Kong

The shares may not be offered or sold in Hong Kong by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32 of the Laws of Hong Kong) (“Companies (Winding Up and Miscellaneous Provisions) Ordinance”) or which do not constitute an invitation to the public within the meaning of the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong) (“Securities and Futures Ordinance”), or (ii) to “professional investors” as defined in the Securities and Futures Ordinance and any rules made thereunder, or (iii) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance, and no advertisement, invitation or document relating to the shares may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which

S-25

are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” in Hong Kong as defined in the Securities and Futures Ordinance and any rules made thereunder.

Singapore

This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares may not be circulated or distributed, nor may the shares be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor (as defined under Section 4A of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”)) under Section 274 of the SFA, (ii) to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA, in each case subject to conditions set forth in the SFA.

Where the shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor, the securities (as defined in Section 239(1) of the SFA) of that corporation shall not be transferable for 6 months after that corporation has acquired the shares under Section 275 of the SFA except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transfer arises from an offer in that corporation’s securities pursuant to Section 275(1A) of the SFA, (3) where no consideration is or will be given for the transfer, (4) where the transfer is by operation of law, (5) as specified in Section 276(7) of the SFA, or (6) as specified in Regulation 32 of the Securities and Futures (Offers of Investments) (Shares and Debentures) Regulations 2005 of Singapore (“Regulation 32”)

Where the shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is a trust (where the trustee is not an accredited investor (as defined in Section 4A of the SFA)) whose sole purpose is to hold investments and each beneficiary of the trust is an accredited investor, the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferable for 6 months after that trust has acquired the shares under Section 275 of the SFA except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transfer arises from an offer that is made on terms that such rights or interest are acquired at a consideration of not less than S$200,000 (or its equivalent in a foreign currency) for each transaction (whether such amount is to be paid for in cash or by exchange of securities or other assets), (3) where no consideration is or will be given for the transfer, (4) where the transfer is by operation of law, (5) as specified in Section 276(7) of the SFA, or (6) as specified in Regulation 32.

Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Act of Japan (Act No. 25 of 1948, as amended), or the FIEA. The securities may not be offered or sold, directly or indirectly, in Japan or to or for the benefit of any resident of Japan (including any person resident in Japan or any corporation or other entity organized under the laws of Japan) or to others for reoffering or resale, directly or indirectly, in Japan or to or for the benefit of any resident of Japan, except pursuant to an exemption from the registration requirements of the FIEA and otherwise in compliance with any relevant laws and regulations of Japan.

S-26

LEGAL MATTERS

Certain legal matters relating to the shares of common stock offered hereby will be passed upon for us by Goodwin Procter LLP. Certain legal matters will be passed upon for the underwriters by Davis Polk & Wardwell LLP.

EXPERTS

The consolidated financial statements of Guidewire Software, Inc. and subsidiaries as of July 31, 2017 and 2016, and for each of the years in the three-year period ended July 31, 2017, and management’s assessment of the effectiveness of internal control over financial reporting as of July 31, 2017, have been incorporated by reference herein and in the registration statement in reliance upon the report of KPMG LLP, independent registered public accounting firm, and upon the authority of said firm as experts in accounting and auditing.

The consolidated financial statements of Cyence, Inc. as of January 31, 2017 and for the year then ended incorporated by reference in this prospectus supplement have been so incorporated in reliance on the report of BDO USA, LLP, independent auditors, given on the authority of said firm as experts in auditing and accounting.

The financial statements of ISCS, Inc. as of and for the year ended December 31, 2016 have been incorporated by reference herein in reliance upon the report of Armanino LLP, independent auditors, and upon the authority of said firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to the common stock offered by this prospectus supplement. This prospectus supplement, filed as part of the registration statement, does not contain all the information set forth in the registration statement and its exhibits and schedules, portions of which have been omitted as permitted by the rules and regulations of the SEC. For further information about us, we refer you to the registration statement and to its exhibits and schedules.

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Exchange Act. You may read and copy any reports, statements or other information on file at the SEC’s public reference facility located at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information regarding its public facilities. Our SEC filings, including the complete registration statement of which this prospectus is a part, are available to the public from commercial document retrieval services and also available at the Internet website maintained by the SEC at http://www.sec.gov.

These documents are also available, free of charge, through the Investors section of our website, which is located at www.ir.guidewire.com. Information contained on, or that can be accessed through, our website is not incorporated by reference into this prospectus supplement or the accompanying prospectus and you should not consider such information to be part of this prospectus supplement or the accompanying prospectus.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus supplement, and information that

S-27

we file later with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and all documents we file pursuant to Section 13(a), 13(c), 14, or 15(d) of the Exchange Act on or after the date of this prospectus supplement and prior to the termination of the offering of our common stock (other than, in each case, documents or information deemed to have been furnished and not filed in accordance with SEC rules):

We are not incorporating by reference (i) any information furnished under items 2.02 or 7.01 (or corresponding information furnished under item 9.01 or included as an exhibit) in any past or future current report on Form 8-K or (ii) any Form S-D, that, in either case, we may file or furnish with the SEC, unless otherwise specified in such current report or in such form or in a particular prospectus supplement. The documents listed above or subsequently filed by us pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act in each year during which the offering made pursuant to this prospectus supplement is in effect prior to the filing with the SEC of our Annual Report on Form 10-K covering such year shall cease to be incorporated by reference in this prospectus from and after the filing of such Annual Reports.

Any statement contained herein shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in any subsequently filed incorporated document modifies or supersedes such statement. Any statement contained in an incorporated document shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein or in any other subsequently filed incorporated document modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

This prospectus supplement is part of a registration statement on Form S-3 filed with the SEC under the Securities Act. This prospectus does not contain all of the information set forth in the registration statement. You should read the registration statement for further information about us.

Documents incorporated by reference herein are available from us, without charge, excluding all exhibits unless specifically incorporated by reference in the documents. You may obtain documents incorporated by reference in this prospectus supplement by writing to us at the following address or by calling us at the telephone number listed below:

Guidewire Software, Inc.

1001 East Hillsdale Blvd., Suite 800

Foster City, California 94404

(650) 357-9100

Attn: General Counsel

S-28

PROSPECTUS

.

Common Stock

Preferred Stock

Senior Debt Securities

Warrants

Units

We may from time to time issue, in one or more series or classes, common stock, preferred stock, senior debt securities, warrants and/or units. We may offer these securities separately or together in units. We will specify in the accompanying prospectus supplement the terms of the securities being offered. We may sell these securities to or through underwriters and also to other purchasers or through agents. We will set forth the names of any underwriters or agents, and any fees, conversions or discount arrangements, in the accompanying prospectus supplement. We may not sell any securities under this prospectus without delivery of the applicable prospectus supplement.

In addition, certain selling securityholders to be identified in a prospectus supplement may use this prospectus from time to time to offer shares of common stock. Specific terms of these securities will be provided in supplements to this prospectus.

You should read this document and any prospectus supplement or amendment carefully before you invest in our securities.

Our common stock is listed on The New York Stock Exchange under the symbol “GWRE.”

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties referenced under the heading “Risk Factors” contained in this prospectus beginning on page 4 and any applicable prospectus supplement, and under similar headings in the other documents that are incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission (“SEC”), 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 March 7, 2018

TABLE OF CONTENTS

All references in this prospectus to “Guidewire,” “the Company,” “we,” “us,” “our” and similar terms refer to Guidewire Software, Inc. and its subsidiaries, unless we state otherwise or the context otherwise requires.

i

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the SEC using a “shelf” registration process. Under this shelf registration process, we may from time to time sell any combination of the securities described in this prospectus 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 one or more prospectus supplements that will contain specific information about the terms of the offering. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and the accompanying prospectus supplement together with the additional information described under the headings “Where You Can Find More Information” and “Incorporation of Certain Documents by Reference”.

You should rely only on the information contained, or incorporated by reference, in this prospectus and any accompanying prospectus, and any free writing prospectus we authorize for use in connection with the applicable offering. We have not authorized anyone to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information in this prospectus, any accompanying prospectus supplement, any document incorporated by reference herein or therein or any free writing prospectus we have authorized for use in connection with the applicable offering is accurate or complete only as of their respective dates, regardless of the time of delivery of this prospectus, the accompanying prospectus supplement and any authorized free writing prospectus. Our business, financial condition, results of operations and prospects may have changed since those dates.

In this prospectus, as permitted by law, we “incorporate by reference” information from other documents that we file with the SEC. This means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus and any accompanying prospectus and should be read with the same care. When we update the information contained in documents that have been incorporated by reference by making future filings with the SEC, the information included or incorporated by reference in this prospectus is considered to be automatically updated and superseded. In other words, in case of a conflict or inconsistency between information contained in this prospectus and information in any accompanying prospectus supplement or incorporated by reference into this prospectus, you should rely on the information contained in the document that was filed later. See “Incorporation of Certain Documents by Reference” in this prospectus.

This prospectus and the accompanying prospectus supplement do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the securities described in the accompanying prospectus supplement or an offer to sell or the solicitation of an offer to buy such securities in any circumstances in which such offer or solicitation is unlawful.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and any accompanying prospectus supplement, including the documents incorporated by reference into this prospectus and any accompanying prospectus supplement, and any free writing prospectus we authorize for use in connection with the applicable offering may contain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended (the “Securities Act”), and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which are subject to risks and uncertainties. These forward-looking statements include statements concerning, among other things, our business strategy (including anticipated trends and developments in, and management plans for, our business and the markets in which we operate), financial results, results of operations, revenues, gross margins, operating expenses, products, projected costs and capital expenditures, research and development programs, sales and marketing initiatives and competition. In some cases, you can identify these statements by forward-looking words, such as “will,” “may,” “might,” “should,” “could,” “estimate,” “expect,” “suggest,” “believe,” “anticipate,” “intend,” “plan” and “continue,” the negative or plural of these words and other comparable terminology.

1

Forward-looking statements are not guarantees of future performance and involve risks and uncertainties. Such forward-looking statements included or incorporated by reference in this prospectus, any accompanying prospectus supplement or any applicable free writing prospectus are based on information available to us as of the date such statements were made and our then-current expectations about future events, which are inherently subject to change and involve risks and uncertainties. You should not place undue reliance on these forward-looking statements. Actual events or results may differ materially from those expressed or implied by these statements due to various factors, including but not limited to the factors discussed under the heading “Item 1A. Risk Factors” in our Annual Report on Form 10-K for the year ended July 31, 2017 and our Quarterly Reports on Form 10-Q for the quarters ended January 31, 2018 and October 31, 2017 and under the heading “Risk Factors” in this prospectus.

We do not undertake any obligation to update any forward-looking statements included or incorporated by reference in this prospectus or any accompanying prospectus supplement or any applicable free writing prospectus, whether as a result of new information, future events, or otherwise, except as required by law. All such forward-looking statements should be read as of the time the statements were made and with the recognition that these forward-looking statements may not be complete or accurate at a later date.

2

THE COMPANY

We provide a technology platform which consists of three elements: core transaction processing, data management and analytics, and digital engagement. Our technology platform supports core insurance operations, including underwriting and policy administration, claim management and billing, enables new insights into data that can improve business decision making and supports digital sales, service and claims experiences for policyholders, agents, and other key stakeholders. Our customers are primarily insurance carriers for property and casualty (“P&C”) insurance.

We began our principal business operations in 2001. To date, we have generated a substantial majority of our software license revenues through annual or quarterly license fees that recur during the term of a customer’s contract and any subsequent renewal periods. We also generate perpetual license revenues and subscription revenues. We anticipate that subscription revenue will increase as a percentage of total revenue as we develop and bring to market more cloud-based solutions to meet increasing industry demand. Thus far, more than 100 customers have subscribed to or licensed one or more applications that are cloud-delivered by us or our partners. Services revenues are primarily derived from implementation and training services performed for our customers. Substantially all of our services revenues are currently billed on a time and materials basis.

Our principal executive offices are located in Foster City, California, and our principal website address is www.guidewire.com. Our office address is 1001 E. Hillsdale Blvd., Suite 800, Foster City, California 94404. Information on or accessible through our Internet website is not part of this prospectus.

3

RISK FACTORS

Investing in our securities involves a high degree of risk. You should carefully consider the risks described in the documents incorporated by reference in this prospectus and any prospectus supplement, as well as other information we include or incorporate by reference into this prospectus and any applicable prospectus supplement, before making an investment decision. Our business, financial condition or results of operations could be materially adversely affected by the materialization of any of these risks. The trading price of our securities could decline due to the materialization of any of these risks, and you may lose all or part of your investment. This prospectus and the documents incorporated herein 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 described in any prospectus supplement and in the documents incorporated herein by reference, including (i) our Annual Report on Form 10-K for the fiscal year ended July 31, 2017, which is on file with the SEC and is incorporated herein by reference, (ii) our Quarterly Reports on Form 10-Q for the quarters ended January 31, 2018 and October 31, 2017, which are on file with the SEC and are incorporated by reference into this prospectus, and (iii) other documents we file with the SEC that are deemed incorporated by reference into this prospectus.

4

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for the periods shown. You should read this table in conjunction with the financial statements and notes incorporated by reference in this prospectus. For the periods indicated below, we had no outstanding shares of preferred stock with required dividend payments. Therefore, the ratios of earnings to combined fixed charges and preferred dividends are the same as the ratios of earnings to fixed charges presented below.

For purposes of calculating the ratios in the table above, earnings consist of pre-tax income from continuing operations before adjustment for income or loss from equity investees and fixed charges. Fixed charges include interest expensed. See Exhibit 12.1 to our Registration Statement on Form S-3 of which this prospectus forms a part for additional detail regarding the computation of the ratio of earnings to fixed charges.

5

USE OF PROCEEDS

We intend to use the net proceeds from the sale of the securities as set forth in the applicable prospectus supplement. We will not receive any proceeds from sales of securities offered by any selling securityholders under this prospectus.

6

DESCRIPTION OF CAPITAL STOCK

Our authorized capital stock consists of 500,000,000 shares of common stock, $0.0001 par value, and 25,000,000 shares of undesignated preferred stock, $0.0001 par value. The following description of our capital stock does not purport to be complete and is subject to, and qualified in its entirety by, our amended and restated certificate of incorporation and bylaws, which are exhibits to the registration statement of which this prospectus forms a part.

Common Stock

As of February 28, 2018, 77,281,302 shares of our common stock were outstanding.

The holders of our common stock are entitled to one vote per share on all matters to be voted on by the stockholders. Subject to preferences that may be applicable to any outstanding shares of preferred stock, holders of common stock are entitled to receive ratably such dividends as may be declared by the board of directors out of funds legally available therefore. In the event we liquidate, dissolve or wind up, holders of common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any outstanding shares of preferred stock. Holders of common stock have no preemptive, conversion or subscription rights. There are no redemption or sinking fund provisions applicable to the common stock. All outstanding shares of common stock are fully paid and nonassessable.

Preferred Stock

Our board of directors may, without further action by our stockholders, fix the rights, preferences, privileges and restrictions of up to an aggregate of 25,000,000 shares of preferred stock in one or more series and authorize their issuance. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of our common stock. Any issuance of our preferred stock could adversely affect the voting power of holders of our common stock and the likelihood that such holders would receive dividend payments and payments upon liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deferring or preventing a change of control or other corporate action.

Registration Rights

Investors’ Rights Agreement

Certain holders of our common stock, or their permitted transferees, are entitled to rights with respect to the registration of these shares under the Securities Act. These rights are provided under the terms of an investor rights agreement between us and the holders of these shares, and include demand registration rights, short-form registration rights and piggyback registration rights. All fees, costs and expenses of underwritten registrations will be borne by us and all selling expenses, including underwriting discounts and selling commissions, will be borne by the holders of the shares being registered.

Demand registration rights. Certain holders of our common stock, or their permitted transferees, are entitled to demand registration rights. Under the terms of the investors’ rights agreement, we will be required, upon the written request of holders of fifty percent (50%) or more of these shares, to use our best efforts to file a registration statement and use reasonable, diligent efforts to effect the registration of all or a portion of these shares for public resale. We are required to effect only two registrations pursuant to this provision of the investors’ rights agreement.

Short form registration rights. Certain holders of our common stock, or their permitted transferees, are also entitled to short form registration rights. If we are eligible to file a registration statement on Form S-3, upon the

7

written request of any of these holders to sell registrable securities at an aggregate price of at least $500,000, we will be required to use our best efforts to effect a registration of such shares. We are required to effect only two registrations pursuant to this provision of the investors’ rights agreement.

Piggyback registration rights. Certain holders of our common stock, or their permitted transferees, are entitled to piggyback registration rights. If we register any of our securities either for our own account or for the account of other securityholders, the holders of these shares are entitled to include their shares in the registration. Subject to certain exceptions, we and the underwriters may limit the number of shares included in the underwritten offering if the underwriters believe that including these shares would adversely affect the offering.

Indemnification. Our investors’ rights agreement contains customary cross-indemnification provisions, under which we are obligated to indemnify the selling stockholders in the event of material misstatements or omissions in the registration statement attributable to us, and they are obligated to indemnify us for material misstatements or omissions attributable to them.

Expiration of Registration Rights. The registration rights granted under the investors’ rights agreement will terminate on the earlier of (i) the seventh anniversary of our initial public offering and (ii) with respect to any holder of registrable securities, the date on which all registrable securities held by such holder can be sold in any three month period without registration under Rule 144.

Registration Rights Agreement in Connection with Cyence Inc. Acquisition

In connection with our acquisition of Cyence Inc., a Delaware corporation (“Cyence”), certain pre-acquisition holders of Cyence capital stock and their affiliates are entitled to certain rights with respect to the registration of shares of our common stock under the Securities Act. These rights are provided under the terms of a registration rights agreement between us and the holders of these shares, and include the obligation that we use our reasonable best efforts to maintain an effective registration statement until the earlier of (i) May 1, 2018 and (ii) the date on which all registrable securities have been be sold or otherwise disposed of pursuant to a registration statement.

Anti-Takeover Effects of Delaware Law and Our Certificate of Incorporation and Bylaws

Certain provisions of Delaware law, our amended and restated certificate of incorporation and our amended and restated bylaws could have the effect of delaying, deferring or discouraging another party from acquiring control of us. These provisions, which are summarized below, may have the effect of discouraging coercive takeover practices and inadequate takeover bids. These provisions are also designed, in part, to encourage persons seeking to acquire control of us to first negotiate with our board of directors. We believe that the benefits of increased protection of our potential ability to negotiate with an unfriendly or unsolicited acquiror outweigh the disadvantages of discouraging a proposal to acquire us because negotiation of these proposals could result in an improvement of their terms.

Limits on ability of stockholders to call a special meeting. Our bylaws provide that special meetings of the stockholders may be called only by a majority of the board of directors then in office. These restrictions may delay the ability of our stockholders to force consideration of a proposal or for holders controlling a majority of our capital stock to take any action, including the removal of directors.

Requirements for advance notification of stockholder nominations and proposals. Our bylaws establish advance notice procedures with respect to stockholder proposals relating to the nomination of candidates for election as directors or new business to be brought before meetings of our stockholders. These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive office not less than 90 days nor more than 120 days prior to the first anniversary date of the annual meeting the

8

preceding year. As a result, our bylaws may have the effect of precluding the conduct of certain business at a meeting if the proper procedures are not followed. These provisions may also discourage or deter a potential acquiror from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company.

No cumulative voting. The Delaware General Corporation Law provides that stockholders are not entitled to the right to cumulate votes in the election of directors unless our amended and restated certificate of incorporation provides otherwise. Our amended and restated certificate of incorporation and amended and restated bylaws do not expressly provide for cumulative voting.

Board Composition and Filling Vacancies. Our certificate of incorporation provides for the division of our board of directors into three classes serving staggered three-year terms, with one class being elected each year. Our certificate of incorporation also provides that directors may be removed only for cause. Furthermore, any vacancy on our board of directors, however occurring, including a vacancy resulting from an increase in the size of our board, may only be filled by the affirmative vote of a majority of our directors then in office even if less than a quorum. The classification of directors, together with the limitations on removal of directors and treatment of vacancies, has the effect of making it more difficult for stockholders to change the composition of our board of directors.

No Written Consent of Stockholders. Our certificate of incorporation provides that all stockholder actions are required to be taken by a vote of the stockholders at an annual or special meeting, and that stockholders may not take any action by written consent in lieu of a meeting. This limit may lengthen the amount of time required to take stockholder actions and would prevent the amendment of our bylaws or removal of directors by our stockholders without holding a meeting of stockholders.

Amendment to Certificate of Incorporation and Bylaws. Any amendment of our certificate of incorporation must first be approved by a majority of our board of directors, and if required by law or our certificate of incorporation, must thereafter be approved by a majority of the outstanding shares entitled to vote on the amendment and a majority of the outstanding shares of each class entitled to vote thereon as a class, except that the amendment of the provisions relating to stockholder action, board composition, limitation of liability and the amendment of our certificate of incorporation must be approved by not less than 66 2/3% of the outstanding shares entitled to vote on the amendment, and not less than 66 2/3% of the outstanding shares of each class entitled to vote thereon as a class. Our bylaws may be amended by the affirmative vote of a majority of the directors then in office, subject to any limitations set forth in the bylaws; and may also be amended by the affirmative vote of a majority of the outstanding shares entitled to vote on the amendment.

Undesignated Preferred Stock. Our certificate of incorporation provides for 25,000,000 authorized shares of preferred stock. The existence of authorized but unissued shares of preferred stock may enable our board of directors to render more difficult or to discourage an attempt to obtain control of us by means of a merger, tender offer, proxy contest or otherwise. For example, if in the due exercise of its fiduciary obligations, our board of directors were to determine that a takeover proposal is not in the best interests of our stockholders, our board of directors could cause shares of preferred stock to be issued without stockholder approval in one or more private offerings or other transactions that might dilute the voting or other rights of the proposed acquirer or insurgent stockholder or stockholder group. In this regard, our certificate of incorporation grants our board of directors broad power to establish the rights and preferences of authorized and unissued shares of preferred stock. The issuance of shares of preferred stock could decrease the amount of earnings and assets available for distribution to holders of shares of common stock. The issuance may also adversely affect the rights and powers, including voting rights, of these holders and may have the effect of delaying, deterring or preventing a change in control of us.

9

Section 203 of the Delaware General Corporation Law

We are subject to the provisions of Section 203 of the Delaware General Corporation Law. In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a three-year period following the time that this stockholder becomes an interested stockholder, unless the business combination is approved in a prescribed manner. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

Section 203 defines a business combination to include:

In general, Section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by the entity or person.

10

DESCRIPTION OF SENIOR DEBT SECURITIES

We may issue senior debt securities, including senior convertible debt, in one or more series. While the terms we have summarized below will apply generally to any future senior debt securities we may offer under this prospectus, the applicable prospectus supplement or free writing prospectus will describe the specific terms of any senior debt securities offered through that prospectus supplement or free writing prospectus. The terms of any senior debt securities we offer under a prospectus supplement or free writing prospectus may differ from the terms we describe below.

We will evidence each series of senior debt securities we will issue by a senior indenture that we enter into with a trustee. We will indicate the name and address of the trustee in the prospectus supplement relating to the particular series of senior debt securities being offered. We have filed a form of senior indenture as an exhibit to the registration statement, of which this prospectus is a part, and supplemental indentures and forms of senior debt securities containing the terms of the senior debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC. Unless the context requires otherwise, whenever we refer to the “indenture,” we also are referring to any supplemental indentures that specify the terms of a particular series of senior debt securities.

The senior indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We use the term “trustee” to refer to the trustee under the senior indenture.

The following summaries of material provisions of the senior debt securities and the senior indenture are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture applicable to a particular series of senior debt securities. We urge you to read the applicable prospectus supplement or free writing prospectus and any related free writing prospectuses related to the senior debt securities that we may offer under this prospectus, as well as the complete applicable indenture that contains the terms of the senior debt securities.

General

We will describe in the applicable prospectus supplement or free writing prospectus the terms of the series of senior debt securities being offered, including:

11

Conversion or Exchange Rights

We will set forth in the applicable prospectus supplement or free writing prospectus the terms on which a series of senior debt securities may be convertible into or exchangeable for our common stock, our preferred stock or other securities (including securities of a third-party). We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock, our preferred stock or other securities (including securities of a third-party) that the holders of the series of senior debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale

Unless we provide otherwise in the prospectus supplement or free writing prospectus applicable to a particular series of senior debt securities, the senior indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of all or substantially all of our assets. However, any successor to or acquirer of such assets must assume all of our obligations under the senior indenture or the senior debt securities, as appropriate. If the senior debt securities are convertible into or exchangeable for other securities of ours or securities of other entities, the person with whom we consolidate or merge or to whom we sell all of our property must make provisions for the conversion of the senior debt securities into securities that the holders of the senior debt securities would have received if they had converted the senior debt securities before the consolidation, merger or sale.

12

Events of Default Under the Indenture

Unless we provide otherwise in the prospectus supplement or free writing prospectus applicable to a particular series of senior debt securities, the following are events of default under the senior indenture with respect to any series of senior debt securities that we may issue:

We will describe in each applicable prospectus supplement or free writing prospectus any additional events of default relating to the relevant series of senior debt securities.

If an event of default with respect to senior debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding senior debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the unpaid principal, premium, if any, and accrued interest, if any, of each issue of senior debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding senior debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the senior indenture, if an event of default under the senior indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under the senior indenture at the request or direction of any of the holders of the applicable series of senior debt securities, unless such holders have offered the trustee indemnity or security satisfactory to it against any loss, liability or expense. The holders of a majority in principal amount of the outstanding senior 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 senior debt securities of that series, provided that:

A holder of the senior debt securities of any series will have the right to institute a proceeding under the senior indenture or to appoint a receiver or trustee, or to seek other remedies if:

13

These limitations do not apply to a suit instituted by a holder of senior debt securities if we default in the payment of the principal, premium, if any, or interest on, the senior debt securities, or other defaults that may be specified in the applicable prospectus supplement or free writing prospectus.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the senior indenture.

Modification of Indenture; Waiver

Subject to the terms of the indenture for any series of senior debt securities that we may issue, we and the trustee may change an indenture without the consent of any holders with respect to the following specific matters:

In addition, under the senior indenture, the rights of holders of a series of senior debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding senior debt securities of each series that is affected. However, subject to the terms of the indenture for any series of senior debt securities that we may issue or as otherwise provided in the prospectus supplement or free writing prospectus applicable to a particular series of senior debt securities, we and the trustee

14

may make the following changes only with the consent of each holder of any outstanding senior debt securities affected:

Discharge

Each indenture provides that, subject to the terms of the indenture and any limitation otherwise provided in the prospectus supplement or free writing prospectus applicable to a particular series of senior debt securities, we can elect to be discharged from our obligations with respect to one or more series of senior debt securities, except for specified obligations, including obligations to:

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium and interest on, the senior debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the senior debt securities of each series only in fully registered form without coupons and, unless we otherwise specify in the applicable prospectus supplement or free writing prospectus, in denominations of $1,000 and any integral multiple thereof. The senior indenture provide that we may issue senior debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company or another depository named by us and identified in a prospectus supplement or free writing prospectus with respect to that series.

At the option of the holder, subject to the terms of the senior indenture and the limitations applicable to global securities described in the applicable prospectus supplement or free writing prospectus, the holder of the senior debt securities of any series can exchange the senior debt securities for other senior debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the senior indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement or free writing prospectus, holders of the senior debt securities may present the senior debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the senior debt securities that the holder presents for transfer or exchange, we will make no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

15

We will name in the applicable prospectus supplement or free writing prospectus the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any senior debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the senior debt securities of each series.

If we elect to redeem the senior debt securities of any series, we will not be required to:

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs.

Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the senior indenture at the request of any holder of senior debt securities unless it is offered security and indemnity satisfactory to it against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement or free writing prospectus, we will make payment of the interest on any senior debt securities on any interest payment date to the person in whose name the senior debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay principal of and any premium and interest on the senior debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement or free writing prospectus, we will make interest payments by check that we will mail to the holder or by wire transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement or free writing prospectus, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to senior debt securities of each series. We will name in the applicable prospectus supplement or free writing prospectus any other paying agents that we initially designate for the senior debt securities of a particular series. We will maintain a paying agent in each place of payment for the senior debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any senior debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

Governing Law

The senior indenture and the senior debt securities will be governed by and construed in accordance with the laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

16

Ranking of Senior Debt Securities

The senior debt securities will rank equally in right of payment to all our other senior debt. The senior indenture does not limit the amount of senior debt securities that we may issue. It also does not limit us from issuing any other secured or unsecured debt.

17

DESCRIPTION OF OTHER SECURITIES

We will set forth in the applicable prospectus supplement a description of any warrants or units issued by us that may be offered and sold pursuant to this prospectus.

18

GLOBAL SECURITIES

Book-Entry, Delivery and Form

Unless we indicate differently in a prospectus supplement, the securities initially will be issued in book-entry form and represented by one or more global securities. The global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, as depositary, or DTC, and registered in the name of Cede & Co., the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC has advised us that it is:

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerized book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, or DTCC. DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes refer to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of the actual purchaser of a security, which we sometimes refer to as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial owners of securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other nominee will not change the beneficial ownership of the securities. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The participants are responsible for keeping account of their holdings on behalf of their customers.

19

So long as the securities are in book-entry form, you will receive payments and may transfer securities only through the facilities of the depositary and its direct and indirect participants. We will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any legal requirements in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities of a particular series are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the securities of such series to be redeemed.

Neither DTC nor Cede & Co. (or such other DTC nominee) will consent or vote with respect to the securities. Under its usual procedures, DTC will mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns the consenting or voting rights of Cede & Co. to those direct participants to whose accounts the securities of such series are credited on the record date, identified in a listing attached to the omnibus proxy.

So long as securities are in book-entry form, we will make payments on those securities to the depositary or its nominee, as the registered owner of such securities, by wire transfer of immediately available funds. If securities are issued in definitive certificated form under the limited circumstances described below, we will have the option of making payments by check mailed to the addresses of the persons entitled to payment or by wire transfer to bank accounts in the United States designated in writing to the applicable trustee or other designated party at least 15 days before the applicable payment date by the persons entitled to payment, unless a shorter period is satisfactory to the applicable trustee or other designated party.

Redemption proceeds, distributions and dividend payments on the securities will be made to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit direct participants’ accounts upon DTC’s receipt of funds and corresponding detail information from us on the payment date in accordance with their respective holdings shown on DTC records. Payments by participants to beneficial owners will be governed by standing instructions and customary practices, as is the case with securities held for the account of customers in bearer form or registered in “street name.” Those payments will be the responsibility of participants and not of DTC or us, subject to any statutory or regulatory requirements in effect from time to time. Payment of redemption proceeds, distributions and dividend payments to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC, is our responsibility, disbursement of payments to direct participants is the responsibility of DTC, and disbursement of payments to the beneficial owners is the responsibility of direct and indirect participants.

Except under the limited circumstances described below, purchasers of securities will not be entitled to have securities registered in their names and will not receive physical delivery of securities. Accordingly, each beneficial owner must rely on the procedures of DTC and its participants to exercise any rights under the securities and the indenture.

The laws of some jurisdictions may require that some purchasers of securities take physical delivery of securities in definitive form. Those laws may impair the ability to transfer or pledge beneficial interests in securities.

DTC may discontinue providing its services as securities depositary with respect to the securities at any time by giving reasonable notice to us. Under such circumstances, in the event that a successor depositary is not obtained, securities certificates are required to be printed and delivered.

20

As noted above, beneficial owners of a particular series of securities generally will not receive certificates representing their ownership interests in those securities. However, if:

We have obtained the information in this section and elsewhere in this prospectus concerning DTC and DTC’s book-entry system from sources that are believed to be reliable, but we take no responsibility for the accuracy of this information.

21

SELLING SECURITYHOLDERS

Information about selling securityholders, where applicable, will be set forth in a prospectus supplement, in a post-effective amendment or in filings we make with the SEC under the Exchange Act that are incorporated by reference.

22

PLAN OF DISTRIBUTION

We or any selling securityholders may offer and sell the securities being offered hereby in one or more of the following ways from time to time:

We will identify the specific plan of distribution, including any underwriters, dealers, agents, or other purchasers, persons, or entities and any applicable compensation, in a prospectus supplement, in an amendment to the registration statement of which this prospectus is a part, or in other filings we make with the SEC under the Exchange Act, which are incorporated by reference.

23

LEGAL MATTERS

Goodwin Procter LLP will pass upon certain legal matters relating to the issuance and sale of the securities offered hereby on behalf of Guidewire Software, Inc. Additional legal matters may be passed upon for us, the selling securityholders or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

EXPERTS

The consolidated financial statements of Guidewire Software, Inc. and subsidiaries as of July 31, 2017 and 2016, and for each of the years in the three-year period ended July 31, 2017, and management’s assessment of the effectiveness of internal control over financial reporting as of July 31, 2017, have been incorporated by reference herein and in the registration statement in reliance upon the report of KPMG LLP, independent registered public accounting firm, and upon the authority of said firm as experts in accounting and auditing.

The consolidated financial statements of Cyence, Inc. as of January 31, 2017 and for the year then ended incorporated by reference in this Prospectus have been so incorporated in reliance on the report of BDO USA, LLP, independent auditors, given on the authority of said firm as experts in auditing and accounting.

The financial statements of ISCS, Inc. as of and for the year ended December 31, 2016 have been incorporated by reference herein in reliance upon the report of Armanino LLP, independent registered public accounting firm, and upon the authority of said firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC under the Exchange Act. You may read and copy any reports, statements or other information on file at the SEC’s public reference facility located at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information regarding its public facilities. Our SEC filings, including the complete registration statement of which this prospectus is a part, are available to the public from commercial document retrieval services and also available at the Internet website maintained by the SEC at http://www.sec.gov.

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information we file with them, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and all documents we file pursuant to Section 13(a), 13(c), 14, or 15(d) of the Exchange Act on or after the date of this prospectus and prior to the termination of the offering under this prospectus (other than, in each case, documents or information deemed to have been furnished and not filed in accordance with SEC rules):

24

We are not incorporating by reference (i) any information furnished under items 2.02 or 7.01 (or corresponding information furnished under item 9.01 or included as an exhibit) in any past or future current report on Form 8-K or (ii) any Form S-D, that, in either case, we may file or furnish with the SEC, unless otherwise specified in such current report or in such form or in a particular prospectus supplement. The documents listed above or subsequently filed by us pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act in each year during which the offering made pursuant to this prospectus is in effect prior to the filing with the SEC of our Annual Report on Form 10-K covering such year shall cease to be incorporated by reference in this prospectus from and after the filing of such Annual Reports.

Any statement contained herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in any subsequently filed incorporated document modifies or supersedes such statement. Any statement contained in an incorporated document shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein or in any other subsequently filed incorporated document modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

This prospectus is part of a registration statement on Form S-3 filed with the SEC under the Securities Act of 1933. This prospectus does not contain all of the information set forth in the registration statement. You should read the registration statement for further information about us.

Documents incorporated by reference herein are available from us, without charge, excluding all exhibits unless specifically incorporated by reference in the documents. You may obtain documents incorporated by reference in this prospectus by writing to us at the following address or by calling us at the telephone number listed below:

Guidewire Software, Inc.

1001 East Hillsdale Blvd., Suite 800

Foster City, California 94404

(650) 357-9100

Attn: General Counsel

You should rely only on the information incorporated by reference or provided in this prospectus or any prospectus supplement. We have not authorized anyone else to provide you with different information. You should not assume that the information in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front page of those documents.

25

$200,000,000

Common Stock

Prospectus Supplement

March     , 2018