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Filed Pursuant to Rule 424(b)(5)
Commission File No. 333-56051

         PROSPECTUS SUPPLEMENT
(To prospectus dated June 15, 1998)

LOGO

$250,000,000

HRPT Properties Trust
5.75% Senior Notes due 2014

        The notes will bear interest at the rate of 5.75% per year. Interest on the notes is payable on February 15 and August 15 of each year, beginning on February 15, 2004. The notes will mature on February 15, 2014. We may redeem some or all of the notes at any time at the redemption price discussed under the caption "Description of the Notes—Optional Redemption of the Notes." If the notes are redeemed on or after August 15, 2013 (180 days prior to the stated maturity of the notes), the redemption price will not include a Make-Whole Amount (as defined herein).

        The notes are unsecured, rank equally with all of our existing and future unsecured and unsubordinated debt, are senior to any future subordinated debt and are effectively junior to any secured debt and to all existing and future debt and other liabilities of our subsidiaries.

        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 related prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

        The aggregate public offering price of the notes is $249,450,000, or 99.780% of the principal amount of each note. We will pay a total underwriting discount of $957,500, or 0.383% of the principal amount of each note. After deducting the underwriting discount, we will receive total proceeds of $248,492,500, or 99.397% of the principal amount of each note.

        Interest on the notes, if any, will accrue from October 30, 2003, to the date of delivery.

        The underwriter expects to deliver the notes to purchasers on or about October 30, 2003.

Citigroup

October 23, 2003

        You should rely only on the information contained in or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information contained in this prospectus supplement or the accompanying prospectus is accurate as of any date other than the date on the front of this prospectus supplement.


TABLE OF CONTENTS

 
   Page
Prospectus Supplement    

Summary
 
S-1
Recent Developments   S-3
Use of Proceeds   S-3
Ratio of Earnings to Fixed Charges   S-3
Description of the Notes   S-4
Material Federal Income Tax Considerations   S-9
Underwriting   S-14
Legal Matters   S-15
Experts   S-15
Incorporation of Certain Information by Reference   S-15
Where You Can Find More Information   S-16
Forward Looking Statements   S-17
Glossary   S-18

Prospectus
 
 
Available Information   ii
Incorporation of Certain Documents by Reference   ii
The Company   1
Use of Proceeds   1
Ratio of Earnings to Fixed Charges   1
Description of Debt Securities   1
Description of Shares   11
Description of Preferred Shares   11
Description of Depositary Shares   17
Description of Warrants   20
Description of Convertible Subordinated Debentures   20
Limitation of Liability; Shareholder Liability   21
Redemption; Business Combinations and Control Share Acquisitions   21
Plan of Distribution   24
Legal Matters   25
Experts   25

        In this prospectus supplement, the terms "HRP," "we," "our" and "us" refer to HRPT Properties Trust and its consolidated subsidiaries unless otherwise noted to exclude consolidated subsidiaries.

(ii)


SUMMARY

        This summary may not contain all of the information that is important to you. You should carefully read this entire prospectus supplement and the accompanying prospectus. You should also read the documents we have referred you to in "Incorporation of Certain Information by Reference."

The Company

        We are a real estate investment trust, or REIT, that owns and leases office properties. As of October 23, 2003, we own 224 properties with 26 million square feet of space costing $3.4 billion. These properties are located in 28 states and the District of Columbia.

        We own a nationwide portfolio of office properties with over 4 million square feet of space leased to the U.S. Government and other government entities. We also own a nationwide portfolio of office properties with over 5 million square feet leased to tenants in medical related businesses. We have focused a large portion of our investments on government and medical tenanted properties because we believe those tenants are less affected by cyclical economic conditions, are more likely to sign long term leases and are more likely to renew their tenancies upon lease expirations than tenants in other businesses.

        In selected areas we have expanded our investments to include office properties leased to commercial tenants generally. Whenever we have expanded by acquiring office properties leased to commercial tenants generally we have tried to purchase high quality properties leased to strong credit quality tenants.

Principal Place of Business

        We are organized as a Maryland real estate investment trust. Our principal place of business is 400 Centre Street, Newton, Massachusetts 02458, and our telephone number is (617) 332-3990.

The Notes

        The following is a brief summary of certain terms of the notes. For a more complete description of the terms of the notes (including the definitions of capitalized terms), see "Description of the Notes" and "Glossary" in this prospectus supplement and "Description of Debt Securities" in the accompanying prospectus.

Securities Offered   $250,000,000 5.75% Senior Notes due 2014.
Maturity   The notes will mature on February 15, 2014, unless previously redeemed.
Interest Payment Dates   Semiannually in arrears on February 15 and August 15 of each year, beginning on February 15, 2004.
Ranking   The notes are our senior unsecured obligations. They are not secured by any of our property or assets, and as a result, you will be one of our unsecured creditors. The notes are not obligations of any of our subsidiaries. The notes will be effectively subordinated to any mortgages and other secured indebtedness we incur and to all indebtedness and other liabilities of our subsidiaries. The notes will rank equally with all of our other unsecured and unsubordinated senior indebtedness, including unsecured senior indebtedness we incur in the future.
         

S-1

Optional Redemption   The notes are redeemable at any time at our option in whole or in part. The redemption price will equal the outstanding principal amount of the notes being redeemed plus accrued interest and the Make-Whole Amount, if any. See "Description of the Notes—Optional Redemption of the Notes." The notes will not have the benefit of a sinking fund.
Use of Proceeds   We estimate that our net proceeds from this offering, after deducting the underwriting discount and other expenses, will be $248.1 million. We intend to use these proceeds to repay amounts outstanding under our revolving bank credit facility and for general business purposes, including acquiring properties or repaying debt.
Limitations on Incurrence of Debt   Various covenants will apply to the notes, including the following:
    (1)   We may not incur Debt if the new Debt would cause our total Debt to be more than 60% of our Adjusted Total Assets.
    (2)   We may not incur Secured Debt if the new Secured Debt would cause our total Secured Debt to be more than 40% of our Adjusted Total Assets.
    (3)   We may not incur Debt if the new Debt would cause the ratio of Consolidated Income Available for Debt Service to Annual Debt Service for our most recently completed four fiscal quarters to be less than 1.5 to 1, determined on a pro forma basis after giving effect to certain assumptions.
    (4)   We are required to maintain Total Unencumbered Assets of at least 200% of Unsecured Debt.

S-2


RECENT DEVELOPMENTS

        Since June 30, 2003, through the date of this prospectus supplement, we have acquired nine properties with an aggregate of 1 million square feet of space located in Connecticut, Massachusetts and New Mexico. The aggregate purchase price for these properties was $126.4 million, including closing costs. In addition, as of the date of this prospectus supplement, we have executed purchase agreements for two additional properties with an aggregate of 134,000 square feet of space and an aggregate purchase price of $22.5 million. These potential acquisitions are subject to our completion of due diligence and customary closing contingencies. Because of these contingencies we can provide no assurances that we will purchase any of these additional properties.

        In the normal course of business we regularly evaluate opportunities to acquire properties. As of the date of this prospectus supplement, we are engaged in multiple negotiations to purchase properties, some of which are material on an individual basis, for purchase prices which would aggregate over $500 million. Some of those negotiations have resulted in executed letters of intent which are non-binding and subject to further negotiation and execution of contracts. We expect that some of these letters of intent will result in signed contracts and it is possible this will occur prior to the closing of this offering. Our acquisitions of properties are generally subject to our satisfaction with due diligence investigation, closing conditions customary in real estate transactions and in some cases other conditions. No assurances can be given as to when or if any of these properties will be acquired. We may also acquire additional properties involving material amounts in the future. We may finance acquisitions with debt, equity issuances or other forms of financing.


USE OF PROCEEDS

        We estimate that the net proceeds from this offering, after deducting the underwriting discount and other expenses, will be $248.1 million. We intend to use the net proceeds from this offering to repay $160 million outstanding under our revolving bank credit facility. The remainder of the proceeds will be used for general business purposes, including acquiring properties or repaying debt. As of October 23, 2003, our $560 million revolving bank credit facility has an outstanding balance of $160 million and an interest rate at LIBOR plus a spread, or 1.9% per annum.


RATIO OF EARNINGS TO FIXED CHARGES

        The ratio of earnings to fixed charges for each of the periods indicated is as follows:

 
    
   Year Ended December 31,
  
 
   Six Months Ended
June 30,
2003

  
 
   2002

   2001

   2000

   1999

   1998

  
 
Ratio of earnings to fixed charges   2.2 x 2.3 x 2.2 x 2.3 x 2.5 x 3.2 x

        The ratios of earnings to fixed charges were computed by dividing earnings by fixed charges. For this purpose, earnings have been calculated by subtracting capitalized interest and adding fixed charges and distributions from equity investments to income before equity in earnings of equity investments and extraordinary items. Fixed charges consist of interest costs, whether expensed or capitalized, the interest component of rental expense, if any, and amortization of debt discounts and deferred financing costs, whether expensed or capitalized.

S-3


DESCRIPTION OF THE NOTES

        The following description of the particular terms of the notes supplements and, to the extent inconsistent with, replaces the description of the general terms and provisions of debt securities set forth under "Description of Debt Securities" on page 1 of the accompanying prospectus.

General

        We will issue the notes under our Indenture dated as of July 9, 1997, and a Supplemental Indenture dated as of October 30, 2003, (together, the "Indenture") between us and U.S. Bank National Association (as successor trustee to State Street Bank and Trust Company), as Trustee. The Indenture is subject to, and governed by, the Trust Indenture Act of 1939, as amended. This prospectus supplement briefly outlines some of the provisions of the Indenture. These summaries are not complete. If you would like more information on these provisions, review the copy of the Indenture that we have filed with the SEC. See "Incorporation of Certain Information by Reference" and "Where You Can Find More Information" in this prospectus supplement and "Available Information" in the accompanying prospectus for information about how to locate these documents. You may also review the Indenture at the Trustee's corporate trust office at One Federal Street, 3rd Floor, Boston, Massachusetts 02110.

        The notes will be a separate series under the Indenture, initially in the aggregate principal amount of $250,000,000. The Indenture does not limit the amount of debt securities that we may issue under the Indenture, and we may issue debt securities in one or more series up to the aggregate initial offering price authorized by us for each series. We may, without the consent of the holders of the notes, reopen this series of notes and issue additional notes under the Indenture in addition to the $250,000,000 of notes authorized as of the date of this prospectus supplement. The additional notes will have the same terms and conditions as the notes offered by this prospectus supplement in all respects, except for issue date, issue price and the first payment of interest thereon. The notes will mature (unless previously redeemed) on February 15, 2014. The notes will be issued only in fully registered form without coupons, in denominations of $1,000 and integral multiples thereof. The notes will be evidenced by a global note in book-entry form, except under the limited circumstances described below under "—Book-Entry System and Form of Notes."

        The notes will be senior unsecured obligations of HRPT Properties Trust, excluding its Subsidiaries, and will rank equally with each other and with all of our other unsecured and unsubordinated indebtedness outstanding from time to time. The notes will be effectively subordinated to our mortgages and other secured indebtedness and to indebtedness and other liabilities of our Subsidiaries and, accordingly, this indebtedness will have to be satisfied in full before you will be able to realize any value from the secured or indirectly held properties. We and our Subsidiaries may incur additional indebtedness, including secured indebtedness, subject to the provisions described below under "—Certain Covenants—Limitations on Incurrence of Debt."

        Except as described under "—Certain Covenants" and "—Merger, Consolidation or Sale" below and under "Description of Debt Securities—Merger, Consolidation or Sale" and "—Certain Covenants" in the accompanying prospectus, the Indenture does not contain any other provisions that would afford you protection in the event of (1) a highly leveraged or similar transaction involving us or any of our affiliates, (2) a change of control or (3) a reorganization, restructuring, merger or similar transaction involving us that may adversely affect you. In addition, subject to the limitations set forth under "—Certain Covenants" and "—Merger, Consolidation or Sale" below or under "Description of Debt Securities—Merger, Consolidation or Sale" and "—Certain Covenants" in the accompanying prospectus, we may enter into certain transactions such as the sale of all or substantially all of our assets or a merger or consolidation that would increase the amount of our indebtedness or substantially reduce or eliminate our assets, which might have an adverse effect on our ability to service our indebtedness, including the notes. We have no present intention of engaging in a highly leveraged or similar transaction.

S-4

Interest and Maturity

        The notes will bear interest at the rate per annum set forth on the cover page of this prospectus supplement from October 30, 2003, or from the immediately preceding Interest Payment Date (as defined below) to which interest has been paid. Interest is payable semiannually in arrears on February 15 and August 15 of each year (the "Interest Payment Dates"), beginning on February 15, 2004, to the persons in whose names the notes are registered in the security register applicable to the notes at the close of business on the date 14 calendar days immediately preceding the applicable Interest Payment Date (the "Regular Record Date"), regardless of whether the Regular Record Date is a Business Day. Accrued interest is also payable on the date of maturity or earlier redemption of the notes. Interest on the notes will be computed on the basis of a 360-day year of twelve 30-day months.

Optional Redemption of the Notes

        We may redeem the notes in whole at any time or in part from time to time before they mature. The redemption price will equal the outstanding principal of the notes being redeemed plus accrued interest and the Make-Whole Amount, if any. If the notes are redeemed on or after August 15, 2013 (180 days prior to the stated maturity of the notes), the redemption price will not include a Make-Whole Amount.

        We are required to give notice of such a redemption not less than 30 days nor more than 60 days prior to the redemption date by first class mail to each holder's address appearing in the securities register maintained by the Trustee. In the event we elect to redeem less than all of the notes, the particular notes to be redeemed will be selected by the Trustee by such method as the Trustee shall deem fair and appropriate.

        We are not required to make any sinking fund or redemption payments prior to the stated maturity of the notes.

Certain Covenants

        Limitations on Incurrence of Debt.    We will not, and will not permit any Subsidiary to:

S-5

        Maintenance of Total Unencumbered Assets.    We and our Subsidiaries will at all times maintain Total Unencumbered Assets of not less than 200% of the aggregate outstanding principal amount of the Unsecured Debt of HRP and its Subsidiaries on a consolidated basis.

        See "Description of Debt Securities—Certain Covenants" in the accompanying prospectus for a description of additional covenants applicable to us.

Merger, Consolidation or Sale

        The Indenture permits us to consolidate with, or sell, lease or convey all or substantially all of our assets to, or merge with or into, any other entity, provided that:

(1)
either we are the continuing entity, or the successor entity (if other than us) formed by or resulting from any such consolidation or merger or which shall have received the transfer of such assets is an entity organized and existing under the laws of the United States or any state thereof and shall expressly assume the due and punctual payment of the principal of (and premium or the Make-Whole Amount on) and any interest on all of the notes and the due and punctual performance and observance of all of the covenants and conditions contained in the Indenture to be performed by us;

(2)
immediately after giving effect to such transaction and treating any indebtedness which becomes an obligation of HRP or any Subsidiary as a result thereof as having been incurred by HRP or such Subsidiary at the time of such transaction, no event of default under the Indenture, and no event which after notice or the lapse of time, or both, would become such an event of default, shall have occurred and be continuing; and

(3)
an officers' certificate and legal opinion covering such conditions is delivered to the Trustee.

S-6

Events of Default, Notice and Waiver

        The Indenture provides that the following events are "events of default" with respect to the notes:

(1)
default for 30 days in the payment of any installment of interest payable on any note when due and payable;

(2)
default in the payment of the principal of (or premium or the Make-Whole Amount on) any note when due and payable;

(3)
default in the performance, or breach, of any covenant of HRP contained in the Indenture (other than a covenant added to the Indenture solely for the benefit of a series of debt securities other than the notes), which continues for 60 days after written notice as provided in the Indenture;

(4)
default under any bond, debenture, note, mortgage, indenture or instrument under which there may be issued or by which there may be secured or evidenced any indebtedness for money borrowed by HRP (or by any Subsidiary, the repayment for which HRP is directly responsible or liable as obligor or guarantor) having an aggregate principal amount outstanding of at least $20,000,000, whether such indebtedness now exists or shall hereafter be incurred or created, which default shall have resulted in such indebtedness becoming or being declared due and payable prior to the date on which it would otherwise have become due and payable, without such indebtedness having been discharged or such acceleration having been rescinded or annulled within a period of 10 days after written notice to HRP by the Trustee or to HRP and the Trustee by the holders of at least 25% in principal amount of the outstanding notes as provided in the Indenture; or

(5)
certain events of bankruptcy, insolvency or reorganization, or court appointment of a receiver, liquidator or trustee of HRP or any Significant Subsidiary or for all or substantially all of either of their property.

        Upon the acceleration of notes in accordance with the terms of the Indenture following the occurrence of an event of default, the principal amount of the notes, plus accrued and unpaid interest thereon and the Make-Whole Amount, will become due and payable. See "Description of Debt Securities—Events of Default, Notice and Waiver" in the accompanying prospectus for a description of rights, remedies and other matters relating to events of default.

Discharge, Defeasance and Covenant Defeasance

        The provisions of the Indenture relating to defeasance and covenant defeasance described under "Description of Debt Securities—Discharge, Defeasance and Covenant Defeasance" in the accompanying prospectus will apply to the notes.

Book-Entry System and Form of Notes

        The notes will be issued in the form of a single fully registered global note without coupons that will be deposited with, or on behalf of, The Depository Trust Company, New York, New York ("DTC"), and registered in the name of its nominee, Cede & Co. This means that we will not issue certificates to each owner of notes. One global note will be issued to DTC, which will keep a computerized record of its participants whose clients have purchased the notes. The participant will then keep a record of its clients who purchased the notes. Unless it is exchanged in whole or in part for a certificated note, the global note may not be transferred, except that DTC, its nominees and their successors may transfer the global note as a whole to one another.

        Beneficial interests in the global note will be shown on, and transfers of the global note will be made only through, records maintained by DTC and its participants.

S-7


        DTC has provided us with the following information: DTC is a limited-purpose trust company organized under the New York Banking Law, a "banking organization" within the meaning of the New York Banking Law, a member of the United States Federal Reserve System, a "clearing corporation" within the meaning of the New York Uniform Commercial Code and a "clearing agency" registered under the provisions of Section 17A of the Exchange Act. DTC holds securities that its participants ("Direct Participants") deposit with DTC. DTC also facilitates the settlement among Direct Participants of securities transactions, such as transfers and pledges, in deposited securities through computerized book-entry changes in the Direct Participants' accounts. This eliminates the need for physical movement of securities certificates. Direct Participants include securities brokers and dealers (including the underwriter), banks, trust companies, clearing corporations and certain other organizations. DTC is owned by a number of its Direct Participants and by the New York Stock Exchange, Inc., the American Stock Exchange LLC and the National Association of Securities Dealers, Inc.

        DTC's book-entry system is also used by other organizations such as securities brokers and dealers, banks and trust companies that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly. The rules that apply to DTC and its Direct Participants are on file with the SEC.

        We expect that, pursuant to procedures established by DTC, Direct Participants will receive credit for the notes on DTC's records and the ownership interest of each beneficial owner is in turn to be recorded on the records of Direct Participants. Neither we nor the Trustee will have any responsibility or liability for any aspect of the records of DTC or any of its Direct Participants or for maintaining, supervising or reviewing any records of DTC or any of its Direct Participants relating to beneficial ownership interests in the notes. The laws of some states require that certain purchasers of securities take physical delivery of such securities in definitive form. Such limits and laws may impair your ability to own, pledge or transfer beneficial interests in the global note.

        So long as DTC or its nominee is the registered owner of the global note, DTC or such nominee, as the case may be, will be considered the sole owner or holder of the notes evidenced by the global note for all purposes under the Indenture. Except as described below, as an owner of a beneficial interest in notes evidenced by the global note you will not be entitled to have any of the individual notes evidenced by such global note registered in your name, you will not receive or be entitled to receive physical delivery of any such notes in definitive form and you will not be considered the owner or holder thereof under the Indenture for any purpose, including with respect to the giving of any direction, instructions or approvals to the Trustee thereunder. Accordingly, you must rely on the procedures of DTC and, if you are not a Direct Participant, on the procedures of the Direct Participant through which you own your interest, to exercise any rights of a "holder" under the Indenture. We understand that, under existing industry practice, if we request any action of holders or if an owner of a beneficial interest in a global note desires to give or take any action which a holder is entitled to give or take under the Indenture, DTC would authorize the Direct Participants holding the relevant beneficial interest to give or take such action, and such Direct Participants would authorize beneficial owners through such Direct Participants to give or take such actions or would otherwise act upon the instructions of beneficial owners holding through them.

        Payments of principal, premium, if any, and interest or additional amounts, if any, on individual notes evidenced by a global note registered in the name of the holder of the global note or its nominee will be made by the Trustee to or at the direction of the holder of the global note or its nominee, as the case may be, as the registered owner of the global note under the Indenture. Under the terms of the Indenture, we and the Trustee may treat the persons in whose name notes, including a global note, are registered as the owners thereof for the purpose of receiving such payments. Consequently, neither we nor the Trustee has or will have any responsibility or liability for the payment of such amounts to beneficial owners of notes (including principal, premium, if any, and interest or additional amounts, if any).

S-8

        DTC's practice is to credit the accounts of relevant Direct Participants on the applicable payment date in accordance with their respective holdings of beneficial interests in the relevant security as shown on the records of DTC. Payments by Direct Participants to the beneficial owners of notes will be governed by standing instructions and customary practice and will be the responsibility of DTC's Direct Participants. Redemption notices with respect to any notes will be sent to the holder of the global note (i.e., DTC, its nominee or any subsequent holder). If less than all of the notes are to be redeemed, we expect the holder of the global note to determine the amount of interest of each Direct Participant in the notes to be redeemed by lot. Neither we, the Trustee, any paying agent nor the security registrar for such notes will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in the global note for such notes.

        Neither we nor the Trustee will be liable for any delay by the holder of a global note, DTC or any Direct Participant in identifying the beneficial owners of notes and we and the Trustee may conclusively rely on, and will be protected in relying on, instructions from the holder of a global note, DTC or any Direct Participant for all purposes.

        The notes, which are evidenced by the global note, will be exchangeable for certificated notes with the same terms in authorized denominations only if:


MATERIAL FEDERAL INCOME TAX CONSIDERATIONS

General

        The following summary of federal income tax considerations is based upon the Internal Revenue Code of 1986, as amended (the "Tax Code"), Treasury regulations, and rulings and decisions now in effect, all of which are subject to change, possibly with retroactive effect, or possible differing interpretations. We have not sought a ruling from the Internal Revenue Service ("IRS") with respect to any matter described in this summary, and we cannot provide any assurance that the IRS or a court will agree with the statements made in this summary. The summary applies to you only if you hold our notes as a capital asset. The summary does not discuss the particular tax consequences that might be relevant to you if you are subject to special rules under the federal income tax law, for example, if you are:

S-9

        In addition, the following summary does not address all possible tax considerations relating to the acquisition, ownership and disposition of our notes, and in particular does not discuss any estate, gift, generation-skipping transfer, state, local or foreign tax considerations. For all these reasons, we urge you to consult with your tax advisor about the federal income tax and other tax consequences of your acquisition, ownership and disposition of our notes.

        For purposes of this summary, you are a "U.S. holder" if you are a beneficial owner of our notes and for federal income tax purposes are:


and if your status as a U.S. holder is not overridden pursuant to the provisions of an applicable tax treaty. Conversely, you are a "non-U.S. holder" if you are a beneficial owner of our notes and are not a U.S. holder.

Tax Consequences for U.S. Holders

        If you are a U.S. holder:

        Payments of Interest.    You must generally include interest on a note in your gross income as ordinary interest income:

        Purchase price for a note that is allocable to prior accrued interest may be treated as offsetting a portion of the interest income from the next scheduled interest payment on the note. Any interest income so offset is not taxable.

        Market Discount.    If you acquire a note and your adjusted tax basis in it upon acquisition is less than its principal amount, you will be treated as having acquired the note at a "market discount" unless the amount of this market discount is less than the de minimis amount (generally 0.25% of the principal amount of the note multiplied by the number of remaining whole years to maturity of the note). Under the market discount rules, you will be required to treat any gain on the sale, exchange, redemption, retirement, or other taxable disposition of a note, or any appreciation in a note in the case of a nontaxable disposition such as a gift, as ordinary income to the extent of the market discount which has not previously been included in your income and which is treated as having accrued on the note at the time of the disposition. In addition, you may be required to defer, until the maturity of the note or earlier taxable disposition, the deduction of all or a portion of the interest expense on any indebtedness incurred or continued to purchase or carry the note. Any market discount will be considered to accrue ratably during the period from the date of your acquisition to the maturity date of the note, unless you elect to accrue the market discount on a constant yield method. In addition, you

S-10


may elect to include market discount in income currently as it accrues, on either a ratable or constant yield method, in which case the rule described above regarding deferral of interest deductions will not apply. This election to include market discount in income currently, once made, applies to all market discount obligations acquired by you during or after the first taxable year to which the election applies and may not be revoked without the consent of the IRS. You should consult with your tax advisor regarding these elections.

        Amortizable Bond Premium.    If you acquire a note and your adjusted tax basis in it upon acquisition is greater than its principal amount, you will be treated as having acquired the note with "bond premium." You generally may elect to amortize this bond premium over the remaining term of the note on a constant yield method, and the amount amortized in any year will be treated as a reduction of your interest income from the note for that year. If the amount of your bond premium amortization would be lower if calculated based on an earlier optional redemption date and the redemption price on that date than the amount of amortization calculated through that date based on the note's maturity date and its stated principal amount, then you must calculate the amount and timing of your bond premium amortization deductions assuming that the note will be redeemed on the optional redemption date at the optional redemption price. You may generally recalculate your bond premium amortization amount and schedule of deductions to the extent your note is not actually redeemed at that earlier optional redemption date. If you do not make an election to amortize bond premium, your bond premium on a note will decrease the gain or increase the loss that you otherwise recognize on a disposition of that note. Any election to amortize bond premium applies to all debt obligations, other than debt obligations the interest on which is excludable from gross income, that you hold at the beginning of the first taxable year to which the election applies and that you thereafter acquire. You may not revoke an election to amortize bond premium without the consent of the IRS. You should consult with your tax advisor regarding this election.

        Disposition of a Note.    Upon the sale, exchange, redemption, retirement or other disposition of a note, you generally will recognize taxable gain or loss in an amount equal to the difference, if any, between (1) the amount you receive in cash or in property, valued at its fair market value, upon this sale, exchange, redemption, retirement or other disposition, other than amounts representing accrued and unpaid interest which will be taxable as interest income, and (2) your adjusted tax basis in the note. Your adjusted tax basis in the note will, in general, equal your acquisition cost for the note, exclusive of any amount paid allocable to prior accrued interest, as increased by any market discount you have included in income in respect of the note, and as decreased by any amortized bond premium on the note. Except with respect to accrued market discount, your gain or loss will be capital gain or loss, and will be long-term capital gain or loss if you have held the note for more than one year at the time of disposition. For noncorporate U.S. holders, preferential rates of tax may apply to long-term capital gains.

Tax Consequences for Non-U.S. Holders

        If you are a non-U.S. holder:

        Generally.    You will not be subject to federal income taxes on payments of principal, premium, if any, or interest on a note, or upon the sale, exchange, redemption, retirement or other disposition of a note, if:

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        The IRS Form W-8 or a substantially similar form must be signed by you under penalties of perjury certifying that you are a non-U.S. holder and providing your name and address, and you must inform the Withholding Agent of any change in the information on the statement within 30 days of the change. If you hold a note through a securities clearing organization or other qualified financial institution, the organization or institution may provide a signed statement to the Withholding Agent. However, in that case, the signed statement must generally be accompanied by a statement containing the relevant information from the executed IRS Form W-8 or substantially similar form that you provided to the organization or institution. If you are a partner in a partnership holding our notes, both you and the partnership must comply with applicable certification requirements.

        Except in the case of income or gain in respect of a note that is effectively connected with the conduct of a United States trade or business, discussed below, interest received or gain recognized by you which does not qualify for exemption from taxation will be subject to U.S. withholding tax at a rate of 30% unless reduced or eliminated by an applicable tax treaty. You must generally use an applicable IRS Form W-8, or a substantially similar form, to claim tax treaty benefits. If you are a non-U.S. holder claiming benefits under an income tax treaty, you should be aware that you may be required to obtain a taxpayer identification number and to certify your eligibility under the applicable treaty's limitations on benefits article in order to comply with the applicable certification requirements of the Treasury regulations.

        Effectively Connected Income and Gain.    If you are a non-U.S. holder whose income and gain in respect of a note is effectively connected with the conduct of a United States trade or business, you will be subject to regular federal income tax on this income and gain in generally the same manner as U.S. holders, and general federal income tax return filing requirements will apply. In addition, if you are a corporation, you may be subject to a branch profits tax equal to 30% of your effectively connected adjusted earnings and profits for the taxable year, unless you qualify for a lower rate under an applicable tax treaty. To obtain an exemption from withholding on interest on the notes that is effectively connected with the conduct of a United States trade or business, you must generally supply to the Withholding Agent an applicable IRS Form W-8, or a substantially similar form.

Information Reporting and Backup Withholding

        Information reporting and backup withholding may apply to interest and other payments to you under the circumstances discussed below. Amounts withheld under backup withholding are generally not an additional tax and may be refunded or credited against your federal income tax liability, provided that you furnish the required information to the IRS. The backup withholding rate is currently 28%.

        If you are a U.S. Holder.    You may be subject to backup withholding when you receive interest payments on a note or proceeds upon the sale, exchange, redemption, retirement or other disposition of a note. In general, you can avoid this backup withholding if you properly execute under penalties of perjury an IRS Form W-9 or a substantially similar form on which you:

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        If you do not provide your correct taxpayer identification number on the IRS Form W-9 or a substantially similar form, you may be subject to penalties imposed by the IRS.

        Unless you have established on a properly executed IRS Form W-9 or a substantially similar form that you are a corporation or come within another enumerated exempt category, interest and other payments on the notes paid to you during the calendar year, and the amount of tax withheld, if any, will be reported to you and to the IRS.

        If you are a Non-U.S. Holder.    The amount of interest paid to you on a note during each calendar year, and the amount of tax withheld, if any, will generally be reported to you and to the IRS. This information reporting requirement applies regardless of whether you were subject to withholding or whether withholding was reduced or eliminated by an applicable tax treaty. Also, interest paid to you on a note may be subject to backup withholding, at the current 28% rate, unless you properly certify your non-U.S. holder status on an IRS Form W-8 or a substantially similar form in the manner described above, under "Tax Consequences for Non-U.S. Holders." Similarly, information reporting and backup withholding will not apply to proceeds you receive upon the sale, exchange, redemption, retirement or other disposition of a note, if you properly certify that you are a non-U.S. holder on an IRS Form W-8 or a substantially similar form. Even without having executed an IRS Form W-8 or a substantially similar form, however, in some cases information reporting and backup withholding may not apply to proceeds you receive upon the sale, exchange, redemption, retirement or other disposition of a note, if you receive those proceeds through a broker's foreign office.

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UNDERWRITING

        Subject to the terms and conditions stated in the underwriting agreement dated the date of this prospectus supplement, Citigroup Global Markets Inc. ("Citigroup") has agreed to purchase, and we have agreed to sell to Citigroup, all of the notes.

        The underwriting agreement provides that the obligation of Citigroup to purchase the notes included in this offering is subject to approval of legal matters by counsel and to other conditions. Citigroup is obligated to purchase all the notes if it purchases any of the notes.

        Citigroup proposes to offer some of the notes directly to the public at the public offering price set forth on the cover page of this prospectus supplement and some of the notes to dealers at the public offering price less a concession not to exceed 0.250% of the principal amount of the notes. Citigroup may allow, and dealers may reallow a concession not to exceed 0.125% of the principal amount of the notes on sales to other dealers. After the initial offering of the notes to the public, Citigroup may change the public offering price and concessions.

        In connection with the offering, Citigroup may purchase and sell notes in the open market. These transactions may include over-allotment, covering and stabilizing transactions. Over-allotment involves sales of notes in excess of the principal amount of notes to be purchased by Citigroup in the offering, which creates a short position. Covering transactions involve purchases of the notes in the open market after the distribution has been completed in order to cover short positions. Stabilizing transactions consist of certain bids or purchases of notes made for the purpose of preventing or retarding a decline in the market price of the notes while the offering is in progress.

        Any of these activities may have the effect of preventing or retarding a decline in the market price of the notes. They may also cause the price of the notes to be higher than the price that otherwise would exist in the open market in the absence of these transactions. Citigroup may conduct these transactions in the over-the-counter market or otherwise. If Citigroup commences any of these transactions, it may discontinue them at any time.

        We estimate that our total expenses, excluding the underwriting discount, for this offering will be $400,000.

        We expect to deliver the notes against payment for the notes on or about October 30, 2003, which is the 5th business day following the date of the pricing of the notes. Under Rule 15c6-1 of the Securities Exchange Act, trades in the secondary market generally are required to settle in three business days, unless the parties to a trade expressly agree otherwise. Accordingly, purchasers who wish to trade notes on the date of pricing or the next succeeding business day will be required, by virtue of the fact that the notes initially will settle in T + 5, to specify alternative settlement arrangements to prevent a failed settlement.

        Citigroup has performed investment banking services for us from time to time for which it has received customary fees and expenses. Citigroup may, from time to time, engage in transactions with and perform services for us in the ordinary course of its business.

        A prospectus in electronic format may be made available on the website maintained by Citigroup. Citigroup may agree to allocate a number of notes for sale to its online brokerage account holders. Citigroup will allocate notes sold to its online brokerage account holders on the same basis as other allocations. In addition, notes may be sold by Citigroup to securities dealers who resell notes to online brokerage account holders.

        We have agreed to indemnify Citigroup against certain liabilities, including liabilities under the Securities Act of 1933 (the "Securities Act"), or to contribute to payments Citigroup may be required to make because of any of those liabilities.

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LEGAL MATTERS

        Sullivan & Worcester LLP, Boston, Massachusetts, our lawyers, will issue an opinion about the legality of the notes. Sidley Austin Brown & Wood LLP, New York, New York, the underwriter's lawyers, will also issue an opinion to the underwriter as to certain matters. Sullivan & Worcester LLP and Sidley Austin Brown & Wood LLP will rely, as to certain matters of Maryland law, upon an opinion of Venable LLP, Baltimore, Maryland. Sidley Austin Brown & Wood LLP will rely, as to certain matters of Massachusetts law, upon the opinion of Sullivan & Worcester LLP. Barry M. Portnoy was a partner in the firm of Sullivan & Worcester LLP until March 1997 and is one of our Managing Trustees. Mr. Portnoy is also a Managing Trustee of two of our former subsidiaries, Hospitality Properties Trust and Senior Housing Properties Trust, and a director and 50% owner of Reit Management & Research LLC, our investment manager. Jennifer B. Clark, our Senior Vice President, was a partner in the firm of Sullivan & Worcester LLP until July 1999. Sullivan & Worcester LLP represents Hospitality Properties Trust, Senior Housing Properties Trust, Reit Management & Research LLC and certain of their affiliates on various matters.


EXPERTS

        The consolidated financial statements and financial statement schedules of HRPT Properties Trust at December 31, 2002 and 2001, and for each of the three years in the period ended December 31, 2002, appearing in our Annual Report on Form 10-K for the year ended December 31, 2002, have been audited by Ernst & Young LLP, independent auditors, as set forth in their report thereon included therein and incorporated herein by reference which, as to the years 2001 and 2000, are based in part on the report of Arthur Andersen LLP, independent public accountants, who audited the financial statements of Hospitality Properties Trust for the years ended December 31, 2001 and prior. The consolidated financial statements and financial statement schedules referred to above are incorporated herein by reference in reliance upon such reports given on the authority of such firms as experts in accounting and auditing.

        In 2002 Arthur Andersen LLP was convicted of obstruction of justice and ceased its audit practice before the SEC. Arthur Andersen LLP had provided its written consent to the incorporation by reference of its report with respect to the audited financial statements of Hospitality Properties Trust into our Annual Report on Form 10-K for the year ended December 31, 2001. A copy of such previously issued report was included in our Annual Report on Form 10-K for the year ended December 31, 2002. Such report was not reissued and Arthur Andersen LLP did not consent to its inclusion in our Annual Report on Form 10-K for the year ended December 31, 2002. Because Arthur Andersen LLP did not consent to the incorporation by reference herein of its audit report in that Annual Report, purchasers of our notes in this offering will not be able to recover against Arthur Andersen LLP under Section 11(a) of the Securities Act. In addition, because of the circumstances that have adversely affected Arthur Andersen LLP, it may not be able to satisfy any claims arising from the provision of auditing services, including claims you may have that are available to security holders under federal and state securities laws.


INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

        The SEC allows us to "incorporate by reference" 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 considered to be part of this prospectus supplement, and information that we subsequently file with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below which were filed with the SEC under the Exchange Act:

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        We also incorporate by reference each of the following documents that we will file with the SEC after the date of this prospectus supplement but before the termination of the notes offering:

        You may request a copy of any of the filings (excluding exhibits), at no cost, by writing or telephoning us at the following address:


WHERE YOU CAN FIND MORE INFORMATION

        You may read and copy any material that we file with the SEC at the SEC's Public Reference Room at 450 Fifth Street, N.W., Washington, D.C. 20549. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. You may also access our SEC filings over the Internet at the SEC's site at http://www.sec.gov.

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FORWARD LOOKING STATEMENTS

        STATEMENTS CONTAINED IN THIS PROSPECTUS SUPPLEMENT AND THE ACCOMPANYING PROSPECTUS, INCLUDING THE DOCUMENTS THAT ARE INCORPORATED BY REFERENCE, THAT ARE NOT HISTORICAL FACTS ARE FORWARD LOOKING STATEMENTS AS DEFINED IN THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995. ALSO, WHEN WE USE ANY OF THE WORDS "BELIEVE," "EXPECT," "ANTICIPATE" OR SIMILAR EXPRESSIONS, WE ARE MAKING FORWARD LOOKING STATEMENTS. FORWARD LOOKING STATEMENTS IN THIS PROSPECTUS SUPPLEMENT INCLUDE STATEMENTS REGARDING THE SECURITY OF OUR RENTAL INCOME AND OUR LEASES, THE CREDIT QUALITY OF OUR TENANTS, THE LIKELIHOOD THAT OUR TENANTS WILL PAY RENT, RENEW LEASES, SIGN LONG TERM LEASES OR BE LESS AFFECTED BY CYCLICAL ECONOMIC CONDITIONS, OUR ACQUISITIONS OF HIGH-QUALITY PROPERTIES, OUR ACCESS TO CAPITAL, OUR ABILITY TO PAY INTEREST AND REPAY PRINCIPAL OF OUR DEBTS, OUR PLANS REGARDING INVESTMENTS, THE TREATMENT OF INCOME ON THE NOTES, REPAYMENT OF AMOUNTS OUTSTANDING UNDER OUR REVOLVING BANK CREDIT FACILITY, FUTURE AVAILABILITY OF BORROWINGS UNDER OUR REVOLVING BANK CREDIT FACILITY, OUR TAX STATUS AS A REAL ESTATE INVESTMENT TRUST AND THE ABILITY OF OUR PROPERTIES TO COMPETE EFFECTIVELY. IN PART, WE HAVE BASED THESE FORWARD LOOKING STATEMENTS ON POSSIBLE OR ASSUMED FUTURE RESULTS OF OUR OR OUR TENANTS' OPERATIONS. FORWARD LOOKING STATEMENTS ARE NOT GUARANTEED. THEY ARE BASED ON OUR PRESENT INTENTIONS AND ON OUR PRESENT EXPECTATIONS AND ASSUMPTIONS. THESE STATEMENTS, INTENTIONS, EXPECTATIONS AND ASSUMPTIONS INVOLVE RISKS AND UNCERTAINTIES, SOME OF WHICH ARE BEYOND OUR CONTROL, THAT COULD CAUSE ACTUAL RESULTS OR EVENTS TO DIFFER MATERIALLY FROM THOSE WE ANTICIPATE OR PROJECT, SUCH AS THE STATUS OF THE ECONOMY, INCLUDING CAPITAL MARKETS AND OUR ABILITY TO ACCESS FINANCING, PROPERTY MARKET CONDITIONS, COMPETITION, CHANGES IN FEDERAL, STATE AND LOCAL LEGISLATION, MAINTENANCE OF OUR TENANT OCCUPANCIES OR LEASE RENTS, AND THE INABILITY TO NEGOTIATE OR CONCLUDE TRANSACTIONS FOR PROPERTIES WHICH WE HAVE IDENTIFIED OR MAY IDENTIFY IN THE FUTURE. PROSPECTIVE PURCHASERS SHOULD NOT PLACE UNDUE RELIANCE ON THESE FORWARD LOOKING STATEMENTS, AS EVENTS DESCRIBED OR IMPLIED IN SUCH STATEMENTS MAY NOT OCCUR. WE UNDERTAKE NO OBLIGATION TO UPDATE OR REVISE ANY FORWARD LOOKING STATEMENTS AS A RESULT OF NEW INFORMATION, FUTURE EVENTS OR OTHERWISE.

        THE AMENDED AND RESTATED DECLARATION OF TRUST ESTABLISHING HRP, DATED JULY 1, 1994, A COPY OF WHICH, TOGETHER WITH ALL AMENDMENTS AND SUPPLEMENTS THERETO, IS DULY FILED IN THE OFFICE OF THE STATE DEPARTMENT OF ASSESSMENTS AND TAXATION OF MARYLAND, PROVIDES THAT THE NAME "HRPT PROPERTIES TRUST" REFERS TO THE TRUSTEES UNDER THE DECLARATION OF TRUST, AS SO AMENDED AND SUPPLEMENTED, COLLECTIVELY AS TRUSTEES, BUT NOT INDIVIDUALLY OR PERSONALLY, AND THAT NO TRUSTEE, OFFICER, SHAREHOLDER, EMPLOYEE OR AGENT OF HRP SHALL BE HELD TO ANY PERSONAL LIABILITY, JOINTLY OR SEVERALLY, FOR ANY OBLIGATION OF, OR CLAIM AGAINST, HRP. ALL PERSONS DEALING WITH HRP, IN ANY WAY, SHALL LOOK ONLY TO THE ASSETS OF HRP FOR THE PAYMENT OF ANY SUM OR THE PERFORMANCE OF ANY OBLIGATION.

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GLOSSARY

        "Acquired Debt" means Debt of a person or entity (1) existing at the time such person or entity becomes a Subsidiary or (2) assumed in connection with the acquisition of assets from such person or entity, in each case, other than Debt incurred in connection with, or in contemplation of, such person or entity becoming a Subsidiary or such acquisition. Acquired Debt is deemed to be incurred on the date of the related acquisition of assets from any person or entity or the date the acquired person or entity becomes a Subsidiary.

        "Annual Debt Service" as of any date means the maximum amount which is expensed in any 12-month period for interest on Debt of HRP and its Subsidiaries.

        "Business Day" means any day other than a Saturday or Sunday or a day on which banking institutions in The City of New York or in the city in which the corporate trust office of the Trustee is located are required or authorized to close.

        "Capital Stock" means, with respect to any entity, any capital stock (including preferred stock), shares, interests, participation or other ownership interests (however designated) of such entity and any rights (other than debt securities convertible into or exchangeable for capital stock), warrants or options to purchase any thereof.

        "Consolidated Income Available for Debt Service" for any period means Earnings from Operations of HRP and its Subsidiaries plus amounts which have been deducted, and minus amounts which have been added, for the following (without duplication): (1) interest on Debt of HRP and its Subsidiaries, (2) provision for taxes of HRP and its Subsidiaries based on income, (3) amortization of debt discount and deferred financing costs, (4) provisions for gains and losses on properties and property depreciation and amortization, (5) the effect of any noncash charge resulting from a change in accounting principles in determining Earnings from Operations for such period and (6) amortization of deferred charges.

        "Debt" of HRP or any Subsidiary means, without duplication, any indebtedness of HRP or any Subsidiary, whether or not contingent, in respect of

(1)
borrowed money or evidenced by bonds, notes, debentures or similar instruments,

(2)
indebtedness for borrowed money secured by any encumbrance existing on property owned by HRP or any Subsidiary, to the extent of the lesser of (x) the amount of indebtedness so secured and (y) the fair market value of the property subject to such encumbrance,

(3)
the reimbursement obligations, contingent or otherwise, in connection with any letters of credit actually issued (other than letters of credit issued to provide credit enhancement or support with respect to other indebtedness of HRP or any Subsidiary otherwise reflected as Debt hereunder) or amounts representing the balance deferred and unpaid of the purchase price of any property or services, except any such balance that constitutes an accrued expense or trade payable, or all conditional sale obligations or obligations under any title retention agreement,

(4)
the principal amount of all obligations of HRP or any Subsidiary with respect to redemption, repayment or other repurchase of any Disqualified Stock, or

(5)
any lease of property by HRP or any Subsidiary as lessee which is reflected on HRP's consolidated balance sheet as a capitalized lease in accordance with GAAP, to the extent, in the case of items of indebtedness under (1) through (3) above, that any such items (other than letters of credit) would appear as a liability on HRP's consolidated balance sheet in accordance with GAAP.

Debt also includes, to the extent not otherwise included, any obligation by HRP or any Subsidiary to be liable for, or to pay, as obligor, guarantor or otherwise (other than for purposes of collection in the ordinary course of business), Debt of another person or entity (other than HRP or any Subsidiary) (it

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being understood that Debt shall be deemed to be incurred by HRP or any Subsidiary whenever HRP or such Subsidiary shall create, assume, guarantee or otherwise become liable in respect thereof).

        "Disqualified Stock" means, with respect to any entity, any Capital Stock of such entity which by the terms of such Capital Stock (or by the terms of any security into which it is convertible or for which it is exchangeable or exercisable), upon the happening of any event or otherwise (1) matures or is mandatorily redeemable, pursuant to a sinking fund obligation or otherwise (other than Capital Stock which is redeemable solely in exchange for common stock or shares), (2) is convertible into or exchangeable or exercisable for Debt or Disqualified Stock, or (3) is redeemable at the option of the holder thereof, in whole or in part (other than Capital Stock which is redeemable solely in exchange for common stock or shares), in each case on or prior to the stated maturity of the notes.

        "Earnings from Operations" for any period means net earnings excluding gains and losses on sales of investments, extraordinary items, gains and losses on early extinguishment of debt, and property valuation losses, as reflected in the financial statements of HRP and its Subsidiaries for such period, determined on a consolidated basis in accordance with GAAP.

        "Make-Whole Amount" means, in connection with any optional redemption or accelerated payment of any notes prior to August 15, 2013, the excess, if any, of (i) the aggregate present value as of the date of such redemption or accelerated payment of each dollar of principal being redeemed or paid and the amount of interest (exclusive of interest accrued to the date of redemption or accelerated payment) that would have been payable in respect of such dollar if such redemption or accelerated payment had been made on August 15, 2013, determined by discounting, on a semiannual basis, such principal and interest at the Reinvestment Rate (determined on the third Business Day preceding the date such notice of redemption is given or declaration of acceleration is made) from the respective dates on which such principal and interest would have been payable if such redemption or accelerated payment had been made on August 15, 2013, over (ii) the aggregate principal amount of the notes being redeemed or paid. In the case of any redemption or accelerated payment of notes on or after August 15, 2013, the Make-Whole Amount means zero.

        "Ratio of Earnings to Fixed Charges" for any period means HRP's earnings divided by fixed charges. For this purpose, earnings have been calculated by subtracting capitalized interest and adding fixed charges and distributions from equity investments to income before equity in earnings of equity investments and extraordinary items. Fixed charges consist of interest costs, whether expensed or capitalized, the interest component of rental expense, if any, and amortization of debt discounts and deferred financing costs, whether expensed or capitalized.

        "Reinvestment Rate" means a rate per annum equal to the sum of 0.30% plus the yield on treasury securities at constant maturity under the heading "Week Ending" published in the Statistical Release under the caption "Treasury Constant Maturities" for the maturity (rounded to the nearest month) corresponding to the remaining life to maturity (which, in the case of maturities corresponding to the principal and interest due on the notes at their maturity, shall be deemed to be August 15, 2013), as of the payment date of the principal being redeemed or paid. If no maturity exactly corresponds to such maturity, yields for the two published maturities most closely corresponding to such maturity shall be calculated pursuant to the immediately preceding sentence and the Reinvestment Rate shall be interpolated or extrapolated from such yields on a straight-line basis, rounding in each of such relevant periods to the nearest month. For purposes of calculating the Reinvestment Rate, the most recent Statistical Release published prior to the date of determination of the Make-Whole Amount shall be used.

        "Secured Debt" means Debt secured by any mortgage, lien, charge, pledge or security interest of any kind.

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        "Significant Subsidiary" means any Subsidiary which is a "significant subsidiary" (within the meaning of Regulation S-X, promulgated by the SEC under the Securities Act) of HRP.

        "Statistical Release" means the statistical release designated "H.15(519)" or any successor publication which is published weekly by the Federal Reserve System and which establishes yields on actively traded United States government securities adjusted to constant maturities or, if such statistical release is not published at the time of any determination under the Indenture, then any publicly available source of similar market data which shall be designated by us.

        "Subsidiary" means any corporation or other entity of which a majority of (1) the voting power of the voting equity securities or (2) the outstanding equity interests are owned, directly or indirectly, by HRP or one or more other Subsidiaries of HRP. For the purposes of this definition, "voting equity securities" means equity securities having voting power for the election of directors, whether at all times or only so long as no senior class of security has such voting power by reason of any contingency.

        "Total Assets" as of any date means the sum of (1) the Undepreciated Real Estate Assets and (2) all other assets of HRP and its Subsidiaries determined in accordance with GAAP (but excluding accounts receivable and intangibles).

        "Total Unencumbered Assets" means the sum of (1) those Undepreciated Real Estate Assets not subject to an encumbrance for borrowed money and (2) all other assets of HRP and its Subsidiaries not subject to an encumbrance for borrowed money determined in accordance with GAAP (but excluding accounts receivable and intangibles).

        "Undepreciated Real Estate Assets" as of any date means the cost (original cost plus capital improvements) of real estate assets of HRP and its Subsidiaries on such date, before depreciation and amortization determined on a consolidated basis in accordance with GAAP.

        "Unsecured Debt" means Debt which is not secured by any of the properties of HRP or any Subsidiary.

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PROSPECTUS

$3,000,000,000

HRPT Properties Trust
 Debt Securities, Preferred Shares of Beneficial Interest, Depositary
Shares, Common Shares of Beneficial Interest and Warrants

        HRPT Properties Trust, formerly known as Health and Retirement Properties Trust (the "Company" or "HRP"), may from time to time offer in one or more series (i) its unsecured debt securities (the "Debt Securities"), (ii) its preferred shares of beneficial interest, par value $.01 per share (the "Preferred Shares"), (iii) fractional shares of the Preferred Shares (the "Depositary Shares"), (iv) its common shares of beneficial interest, par value $.01 per share (the "Common Shares"), or (v) warrants to purchase any of the above securities (the "Warrants"), with an aggregate public offering price of up to $3,000,000,000 on terms to be determined at the time of offering. The Debt Securities, Preferred Shares, Depositary Shares, Common Shares and Warrants (collectively, the "Offered Securities") may be offered, separately or together, in separate series, in amounts, at prices and on terms to be set forth in a supplement to this Prospectus (a "Prospectus Supplement").

        The specific terms of the Offered Securities in respect of which this Prospectus is being delivered will be set forth in the applicable Prospectus Supplement and will include, where applicable: (i) in the case of Debt Securities, the specific title, aggregate principal amount, currency, form (which may be registered or bearer, or certificated or global), authorized denominations, maturity, rate (or manner of calculation thereof) and time of payment of interest, terms for redemption at the option of the Company or repayment at the option of the holder, terms for sinking fund payments, terms for conversion into Preferred Shares, Depositary Shares or Common Shares, terms for subordination to other indebtedness of the Company, any original issue discount and any initial public offering price; (ii) in the case of Preferred Shares, the specific title and stated value, any dividend, liquidation, redemption, conversion, voting and other rights, and any initial public offering price; (iii) in the case of Depositary Shares, the fractional shares of Preferred Shares represented by each Depositary Share, (iv) in the case of Common Shares, any offering price; and (v) in the case of Warrants, the securities to which they relate, duration, offering price, exercise price and detachability.

        The applicable Prospectus Supplement will also contain information, where applicable, about certain United States federal income tax considerations relating to, and any listing on a securities exchange of, the Offered Securities covered by such Prospectus Supplement.

THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

        The Offered Securities may be offered directly, through agents designated from time to time by the Company or to or through underwriters or dealers. If any agents or underwriters are involved in the sale of any of the Offered Securities, their names, and any applicable purchase price, fee, commission or discount arrangement between or among them, will be set forth, or will be calculable from the information set forth, in an accompanying Prospectus Supplement. See "Plan of Distribution." No Offered Securities may be sold without delivery of a Prospectus Supplement describing the method and terms of the offering of such Offered Securities.

The date of this Prospectus is June 15, 1998.

        No person has been authorized to give any information or to make any representations other than those contained or incorporated by reference in this Prospectus in connection with the offer contained in this Prospectus and, if given or made, such information or representations must not be relied upon as having been authorized by the Company or any underwriters, agents or dealers. This Prospectus does not constitute an offer to sell or solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation. Neither the delivery of this Prospectus nor any sale made hereunder shall, under any circumstances, create an implication that there has been no change in the affairs of the Company and its subsidiaries since the date hereof or the information contained or incorporated by reference herein is correct at any time subsequent to the date hereof.


AVAILABLE INFORMATION

        The Company has filed with the Securities and Exchange Commission (the "Commission") in Washington, D.C., a registration statement on Form S-3 (together with all exhibits, schedules and amendments thereto, the "Registration Statement") under the Securities Act of 1933, as amended (the "Securities Act"), with respect to the Offered Securities. This Prospectus, which is a part of the Registration Statement, does not contain all of the information set forth in the Registration Statement. Statements in this Prospectus as to the contents of any contract or other document are not necessarily complete, and in each instance reference is made to the copy of such contract or other documents filed as an exhibit to the Registration Statement, each such statement being qualified in all respects by such reference and the exhibits and schedules thereto. For further information concerning the Company and the Offered Securities, reference is made to the Registration Statement. Copies of the Registration Statement may be obtained from the Commission at its principal office in Washington, D.C. upon payment of the prescribed fee.

        The Company is subject to the informational requirements of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and, in accordance therewith, files reports and other information with the Commission. The Registration Statement, the exhibits and schedules forming a part thereof and the reports, proxy statements and other information filed by the Company with the Commission can be inspected and copies obtained at the public reference facilities maintained by the Commission at Judiciary Plaza, Room 1024, 450 Fifth Street, N.W., Washington, D.C. 20549, and at the following regional offices of the Commission: Chicago Regional Office, Suite 1400, 500 West Madison Street, Chicago, Illinois 60661-2511; and New York Regional Office, Seven World Trade Center, New York, New York 10048. Copies of such material can be obtained at prescribed rates from the Public Reference Section of the Commission at its principal office at 450 Fifth Street, N.W., Washington, D.C. 20549. The Commission maintains a World Wide Web site that contains reports, proxy and information statements and other information regarding registrants, including the Company, that file electronically with the Commission. The address of the site is http://www.sec.gov. The Company's Common Shares are traded on the New York Stock Exchange ("NYSE") under the symbol "HRP," and similar information concerning the Company may be inspected at the office of the NYSE at 20 Broad Street, New York, New York 10005.


INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

        The following documents, which have been filed with the Commission pursuant to the Exchange Act, are hereby incorporated in this Prospectus and specifically made a part hereof by reference: (i) the Company's Current Reports on Form 8-K dated February 11, 1998, February 12, 1998, February 17, 1998, February 18, 1998, February 19, 1998, February 27, 1998, March 19, 1998, March 24, 1998, March 30, 1998, April 10, 1998, April 14, 1998, May 11, 1998, May 22, 1998 and May 27, 1998, (ii) the Company's Quarterly Report on Form 10-Q for the fiscal quarter ended March 31, 1998 and (iii) the Company's Annual Report on Form 10-K for the year ended December 31, 1997. All documents filed by the Company pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of this Prospectus and prior to the termination of the offering of the Offered Securities shall be deemed to be incorporated by reference into this Prospectus and to be a part hereof from the respective dates of filing of such documents.

        Any statement contained herein or in a document incorporated or deemed to be incorporated herein by reference shall be deemed to be modified or superseded for purposes of this Prospectus to the extent that a statement contained herein (or in the applicable Prospectus Supplement), or in any subsequently filed document that also is or is deemed to be incorporated herein by reference, 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.

(ii)

        The Company hereby undertakes to provide without charge to each person to whom this Prospectus is delivered, upon the written or oral request of such person, a copy of any and all of the information that has been incorporated by reference in this Prospectus (excluding exhibits unless such exhibits are specifically incorporated by reference into the information that this Prospectus incorporates). Requests for such copies should be made to the Company at its principal executive offices, 400 Centre Street, Newton, Massachusetts 02158, Attention: Investor Relations, telephone (617) 332-3990.

(iii)


THE COMPANY

        The Company is a real estate investment trust ("REIT") which invests in healthcare related real estate and office buildings. As of June 2, 1998, the Company directly owned 207 properties representing an aggregate investment of $2.5 billion (at cost), had mortgage investments in 29 properties aggregating $85.2 million and had a 9.3% equity investment in Hospitality Properties Trust ("HPT"), a New York Stock Exchange-listed REIT founded by the Company which invests in hotels, of approximately $100 million (at cost), for total real estate investments of approximately $2.7 billion located in 34 states and the District of Columbia. At the Company's 1998 annual meeting of shareholders, the shareholders voted to approve a change of the Company's name to "HRPT Properties Trust." The Company expects the name change to become effective during the summer of 1998.

        The Company is organized as a Maryland real estate investment trust. The Company's principal place of business is 400 Centre Street, Newton, Massachusetts 02158 and its telephone number is (617) 332-3990.


USE OF PROCEEDS

        Unless otherwise described in the applicable Prospectus Supplement, the Company intends to use the net proceeds from the sale of the Offered Securities for general business purposes, which may include the acquisition of, or other investments in, income producing real estate, including retirement communities, assisted living centers, long-term care facilities, medical office and other office buildings and office buildings leased to various agencies of the United States Government, and the repayment of indebtedness outstanding at such time or the reduction of amounts outstanding under the Company's credit facilities. Pending utilization as set forth above, the proceeds from the sale of the Offered Securities will be invested in short term investments, including repurchase agreements. Such investments may not be investment grade.


RATIO OF EARNINGS TO FIXED CHARGES

        The following table sets forth the Company's consolidated ratios of earnings to fixed charges for the periods indicated:

 
    
   For the years ended December 31,
 
   For the quarter ended
March 31, 1998
 
   1997
   1996
   1995
   1994
   1993
Ratio of earnings to fixed charges   3.2x   3.9x   4.3x   3.4x   6.7x   6.8x

        The ratios of earnings to fixed charges presented above were computed by dividing the Company's earnings by fixed charges. For this purpose, earnings have been calculated by adding fixed charges to income before income taxes, extraordinary items and gain or loss on the disposition of real property. Fixed charges consist of interest costs, whether expensed or capitalized, the interest component of rental expense, if any, amortization of debt discounts and deferred financing costs, whether expensed or capitalized. To date, the Company has not issued any Preferred Shares; therefore, the ratio of earnings to combined fixed charges and Preferred Shares distributions are the same as the ratios of earnings to fixed charges presented above.


DESCRIPTION OF DEBT SECURITIES

        The Debt Securities will be issued under one or more indentures (an "Indenture") between the Company and a trustee (an "Indenture Trustee"). Any Indenture will be subject to, and governed by, the Trust Indenture Act of 1939, as amended (the "TIA"). The statements made hereunder relating to any Indentures and the Debt Securities to be issued thereunder are summaries of certain anticipated provisions thereof and do not purport to be complete and are subject to, and are qualified in their entirety by reference to, all provisions of the Indentures and such Debt Securities.

General

        The Company has filed with its Registration Statement with respect to the Offered Securities a form of Indenture (as supplemented from time to time, the "Senior Indenture") relating to the Senior Securities (as defined) and a form of Indenture (as supplemented from time to time, the "Subordinated Indenture") relating to the Subordinated Securities (as defined). The Debt Securities will be direct, unsecured obligations of the Company

1

and, if issued under the Senior Indenture, will rank equally and ratably with other unsecured and unsubordinated indebtedness of the Company (the "Senior Securities"), or, if issued under the Subordinated Indenture, will be subordinated in right of payment to the prior payment in full of Senior Indebtedness (as defined in the applicable Prospectus Supplement) ("Subordinated Securities"). See "—Subordination". The Debt Securities may be issued without limit as to aggregate principal amount, in one or more series, in each case as established from time to time in or pursuant to authority granted by a resolution of the Board of Trustees of the Company (the "Trustees") or as established in one or more indentures supplemental to any Indenture. All Debt Securities of one series need not be issued at the same time and, unless otherwise provided, a series may be reopened, without the consent of the holders of the Debt Securities of such series, for issuances of additional Debt Securities of such series.

        It is anticipated that any Indenture will provide that the Company may, but need not, designate more than one Indenture Trustee thereunder, each with respect to one or more series of Debt Securities. Any Indenture Trustee under any Indenture may resign or be removed with respect to one or more series of Debt Securities, and a successor Indenture Trustee may be appointed to act with respect to such series. In the event that two or more persons are acting as Indenture Trustee with respect to different series of Debt Securities, each such Indenture Trustee shall be a trustee of a trust under the applicable Indenture separate and apart from the trust administered by any other Indenture Trustee, and, except as otherwise indicated herein, any action described herein to be taken by the Indenture Trustee may be taken by each such Indenture Trustee with respect to, and only with respect to, the one or more series of Debt Securities for which it is Indenture Trustee under the applicable Indenture.

        Reference is made to the Prospectus Supplement relating to the series of Debt Securities being offered for the specific terms thereof, including, where applicable, the following:

2

        The Debt Securities may provide for less than the entire principal amount thereof to be payable upon declaration of acceleration of the maturity thereof ("Original Issue Discount Securities"). If material or applicable, special U.S. federal income tax, accounting and other considerations applicable to Original Issue Discount Securities will be described in the applicable Prospectus Supplement.

        Except as described under "—Merger, Consolidation or Sale" or as may be set forth in any Prospectus Supplement, an Indenture will not contain any other provisions that would limit the ability of the Company to incur indebtedness or that would afford holders of the Debt Securities protection in the event of a highly leveraged or similar transaction involving the Company. However, restrictions on ownership and transfers of the Company's capital stock, designed to preserve its status as a REIT, may act to prevent or hinder a change of control. See "Redemption; Business Combinations and Control Share Acquisitions." Reference is made to the applicable Prospectus Supplement for information with respect to any deletions from, modifications of or additions to the

3

events of default or covenants that are described below, including any addition of a covenant or other provisions providing event risk or similar protection.

Denominations, Interest, Registration and Transfer

        Unless otherwise described in the applicable Prospectus Supplement, the Debt Securities of any series which are registered securities, other than registered securities issued in global form (which may be of any denomination), shall be issuable in denominations of $1,000 and any integral multiple thereof.

        Unless otherwise specified in the applicable Prospectus Supplement, the principal of (and premium, if any) and interest on any series of Debt Securities will be payable at the corporate trust office of the Indenture Trustee, initially at the address which will be set forth in the applicable Prospectus Supplement; provided that, at the option of the Company, payment of interest may be made by check mailed to the address of the person entitled thereto as it appears in the applicable register or by wire transfer of funds to such person at an account maintained within the United States.

        Any interest not punctually paid or duly provided for on any interest payment date with respect to a Debt Security ("Defaulted Interest") will forthwith cease to be payable to the holder on the applicable regular record date and may either be paid to the person in whose name such Debt Security is registered at the close of business on a special record date (the "Special Record Date") for the payment of such Defaulted Interest to be fixed by the applicable Indenture Trustee, notice whereof shall be given to the holder of such Debt Security not less than 10 days prior to such Special Record Date, or may be paid at any time in any other lawful manner, all as more completely described in the applicable Indenture.

        Subject to certain limitations imposed upon Debt Securities issued in book-entry form, the Debt Securities of any series will be exchangeable for other Debt Securities of the same series and of a like aggregate principal amount and tenor of different authorized denominations upon surrender of such Debt Securities at the corporate trust office of the applicable Indenture Trustee. In addition, subject to certain limitations imposed upon Debt Securities issued in book-entry form, the Debt Securities of any series may be surrendered for conversion or registration of transfer thereof at the corporate trust office of the applicable Indenture Trustee. Every Debt Security surrendered for conversion, registration of transfer or exchange shall be duly endorsed or accompanied by a written instrument of transfer. No service charge will be made for any registration of transfer or exchange of any Debt Securities, but the Indenture Trustee or the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. If the applicable Prospectus Supplement refers to any transfer agent (in addition to the Indenture Trustee) initially designated by the Company with respect to any series of Debt Securities, the Company may at any time rescind the designation of any such transfer agent or approve a change in the location through which any such transfer agent acts, except that the Company will be required to maintain a transfer agent in each place of payment for such series. The Company may at any time designate additional transfer agents with respect to any series of Debt Securities.

        Neither the Company nor any Indenture Trustee shall be required to (i) issue, register the transfer of or exchange Debt Securities of any series during a period beginning at the opening of business 15 days before any selection of Debt Securities of that series to be redeemed and ending at the close of business on (a) if such Debt Securities are issuable only as registered securities, the day of the mailing of the relevant notice of redemption and (b) if such Debt Securities are issuable as bearer securities, the day of the first publication of the relevant notice of redemption or, if such Debt Securities are also issuable as registered securities and there is no publication, the mailing of the relevant notice of redemption, or (ii) to register the transfer of or exchange any registered security so selected for redemption in whole or in part, except, in the case of any registered security to be redeemed in part, the portion thereof not to be redeemed, or (iii) to exchange any bearer security so selected for redemption except that such a bearer security may be exchanged for a registered security of that series and like tenor; provided that such registered security shall be simultaneously surrendered for redemption, or (iv) to issue, register the transfer of or exchange any Debt Security which has been surrendered for repayment at the option of the holder, except the portion, if any, of such Debt Security not to be so repaid.

4

Merger, Consolidation or Sale

        The Company may consolidate with, or sell, lease or convey all or substantially all of its assets to, or merge with or into, any other entity; provided that (i) either the Company shall be the continuing entity or the successor entity (if other than the Company) formed by or resulting from any such consolidation or merger or which shall have received the transfer of such assets shall expressly assume payment of the principal of (and premium, if any) and interest on all of the Debt Securities and the due and punctual performance and observance of all of the covenants and conditions contained in any Indenture; (ii) immediately after giving effect to such transaction and treating any indebtedness which becomes an obligation of the Company or any subsidiary as a result thereof as having been incurred by the Company or such subsidiary at the time of such transaction, no event of default under any Indenture, and no event which, after notice or the lapse of time, or both, would become such an event of default, shall have occurred and be continuing; and (iii) an officer's certificate and legal opinion covering such conditions shall be delivered to the Indenture Trustee.

Certain Covenants

        Existence.    Except as permitted under "—Merger, Consolidation or Sale," the Company will be required to do or cause to be done all things necessary to preserve and keep in full force and effect its corporate existence, rights (charter and statutory) and franchises; provided, however, that the Company shall not be required to preserve any right or franchise if it determines that the preservation thereof is no longer desirable in the conduct of its business.

        Provision of Financial Information.    Whether or not the Company is subject to Section 13 or 15(d) of the Exchange Act, the Company will, to the extent permitted under the Exchange Act, file with the Commission the annual reports, quarterly reports and other documents which the Company would have been required to file with the Commission pursuant to such Section 13 or 15(d) (the "Financial Statements") if the Company were so subject, such documents to be filed with the Commission on or prior to the respective dates (the "Required Filing Dates") by which the Company would have been required so to file such documents if the Company were so subject. The Company will also in any event (i) within 15 days of each Required Filing Date (a) transmit by mail to all holders of Debt Securities, as their names and addresses appear in the Company's security register, without cost to such holders, copies of the annual reports and quarterly reports which the Company would have been required to file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act if the Company were subject to such Sections, and (b) file with the applicable Indenture Trustee copies of the annual reports, quarterly reports and other documents which the Company would have been required to file with the Commission pursuant to Section 13 or 15(d) of the Exchange Act if the Company were subject to such Sections, and (ii) if filing such documents by the Company with the Commission is not permitted under the Exchange Act, promptly upon written request and payment of the reasonable cost of duplication and delivery, supply copies of such documents to any prospective holder of Debt Securities.

        Additional Covenants.    Any additional or different covenants of the Company with respect to any series of Debt Securities will be set forth in the applicable Prospectus Supplement.

Events of Default, Notice and Waiver

        Each Indenture will provide that the following events are "Events of Default" with respect to any series of Debt Securities issued thereunder: (a) default for 30 days in the payment of any installment on any Debt Security of such series; (b) default in the payment of the principal of (or premium, if any, on) any Debt Security of such series at its maturity; (c) default in making any sinking fund payments as required for any Debt Security of such series; (d) default in the performance of any other covenant of the Company contained in the applicable Indenture (other than a covenant added to such Indenture solely for the benefit of a series of Debt Securities issued thereunder other than such series), such default having continued for 60 days after written notice as provided in such Indenture; (e) default in the payment of an aggregate principal amount exceeding a specified dollar amount of any evidence of indebtedness of the Company or any mortgage, indenture or other instrument under which such indebtedness is issued or by which such indebtedness is secured, such default having occurred after the expiration of any applicable grace period and having resulted in the acceleration of the maturity of such indebtedness, but only if such indebtedness is not discharged or such acceleration is not rescinded or annulled; (f) certain events of bankruptcy, insolvency or reorganization, or court appointment of a receiver, liquidator or trustee of the Company

5

or any Significant Subsidiary (as hereinafter defined) or any of their respective property; and (g) any other event of default provided with respect to a particular series of Debt Securities. The term "Significant Subsidiary" means each significant subsidiary (as defined in Regulation S-X promulgated under the Securities Act) of the Company.

        If an Event of Default (other than an Event of Default described in clause (f) above) under any Indenture with respect to Debt Securities of any series at the time outstanding occurs and is continuing, then in every such case the applicable Indenture Trustee or the holders of not less than a majority in principal amount of the outstanding Debt Securities of that series may declare the principal amount (or, if the Debt Securities of that series are Original Issue Discount Securities or indexed securities, such portion of the principal amount as may be specified in the terms thereof) of all of the Debt Securities of that series to be due and payable immediately by written notice thereof to the Company (and to the applicable Indenture Trustee if given by the holders). If an Event of Default described in clause (f) above with respect to the Debt Securities of any series at the time outstanding shall occur, the principal amount of all the Debt Securities of that series (or, in the case of any such Original Issue Discount Security or other Debt Security, such specified amount) will automatically, and without any action by the Indenture Trustee or any holder of such series of Debt Securities, become immediately due and payable. However, at any time after such a declaration of acceleration with respect to Debt Securities of such series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be) has been made, but before a judgment or decree for payment of the money due has been obtained by the applicable Indenture Trustee, the holders of not less than a majority in principal amount of outstanding Debt Securities of such series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be) may rescind and annul such declaration and its consequences if (i) the Company shall have deposited with the applicable Indenture Trustee all required payments of the principal of (and premium, if any) and interest on the Debt Securities of such series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be), plus certain fees, expenses, disbursements and advances of the applicable Indenture Trustee, and (ii) all Events of Default, other than the non-payment of accelerated principal (or specified portion thereof), or premium, if any, or interest on the Debt Securities of such series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be) have been cured or waived as provided in the applicable Indenture. Each of the Indentures will also provide that the holders of not less than a majority in principal amount of the outstanding Debt Securities of any series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be) may waive any past default with respect to such series and its consequences, except a default (i) in the payment of the principal of (or premium, if any) or interest on any Debt Security of such series or (ii) in respect of a covenant or provision contained in the applicable Indenture that cannot be modified or amended without the consent of the holder of each outstanding Debt Security affected thereby.

        The Indenture Trustee will be required to give notice to the holders of Debt Securities within 90 days of a default under the applicable Indenture unless such default has been cured or waived; provided, however, that such Indenture Trustee may withhold notice to the holders of any series of Debt Securities of any default with respect to such series (except a default in the payment of the principal of (or premium, if any) or interest on any Debt Security of such series or in the payment of any sinking fund installment in respect of any Debt Security of such series) if specified responsible officers of such Indenture Trustee consider such withholding to be in the interest of such holders.

        Each Indenture will provide that no holders of Debt Securities of any series may institute any proceedings, judicial or otherwise, with respect to the Indenture or for any remedy thereunder, except in the case of failure of the Indenture Trustee, for 60 days, to act after it has received a written request to institute proceedings in respect of an event of default from the holders of not less than a majority in principal amount of the outstanding Debt Securities of such series, as well as an offer of reasonable indemnity. This provision will not prevent, however, any holder of Debt Securities from instituting suit for the enforcement of payment of the principal of (and premium, if any) and interest on such Debt Securities at the respective due dates thereof.

        Subject to provisions in the applicable Indenture relating to its duties in case of default, no Indenture Trustee will be under any obligation to exercise any of its rights or powers under such Indenture at the request or direction of any holders of any series of Debt Securities then outstanding under such Indenture, unless such holders shall have offered to the Indenture Trustee reasonable security or indemnity. The holders of not less than a majority in principal amount of the outstanding Debt Securities of any series (or of all Debt Securities then outstanding under the applicable Indenture, as the case may be) shall have the right to direct the time, method and place of

6

conducting any proceeding for any remedy available to the applicable Indenture Trustee, or of exercising any trust or power conferred upon such Indenture Trustee. However, an Indenture Trustee may refuse to follow any direction which is in conflict with any law or the Indenture, which may involve such Indenture Trustee in personal liability or which may be unduly prejudicial to the holders of Debt Securities of such series not joining therein.

        The Company will be required to deliver to each Indenture Trustee annually a certificate, signed by one of several specified officers of the Company, stating whether or not such officer has knowledge of any default under the applicable Indenture and, if so, specifying each such default and the nature and status thereof.

Modification of the Indenture

        Modifications and amendments of an Indenture will be permitted to be made only with the consent of the holders of not less than a majority in principal amount of all outstanding Debt Securities or series of outstanding Debt Securities which are affected by such modification or amendment; provided, however, that no such modification or amendment may, without the consent of the holder of each such Debt Security affected thereby, (i) change the stated maturity of the principal of, or any installment of interest (or premium, if any) on any such Debt Security; (ii) reduce the principal amount of, or the rate or amount of interest on, or any premium payable on redemption of, any such Debt Security, or reduce the amount of principal of an Original Issue Discount Security that would be due and payable upon declaration of acceleration of the maturity thereof or would be provable in bankruptcy, or adversely affect any right of repayment of the holder of any such Debt Security; (iii) change the place of payment, or the coin or currency, for payment of principal of, premium, if any, or interest on any such Debt Security; (iv) impair the right to institute suit for the enforcement of any payment on or with respect to any such Debt Security; (v) reduce the above-stated percentage of outstanding Debt Securities of any series necessary to modify or amend the Indenture, to waive compliance with certain provisions thereof or certain defaults and consequences thereunder or to reduce the quorum or voting requirements set forth in such Indenture; or (vi) modify any of the foregoing provisions or any of the provisions relating to the waiver of certain past defaults or certain covenants, except to increase the required percentage to effect such action or to provide that certain other provisions may not be modified or waived without the consent of the holder of such Debt Security.

        Each Indenture will provide that the holders of not less than a majority in principal amount of a series of outstanding Debt Securities have the right to waive compliance by the Company with certain covenants relating to such series of Debt Securities in such Indenture.

        Modifications and amendments of an Indenture will be permitted to be made by the Company and the applicable Indenture Trustee thereunder without the consent of any holder of Debt Securities for any of the following purposes: (i) to evidence the succession of another person to the Company as obligor under such Indenture; (ii) to add to the covenants of the Company for the benefit of the holders of all or any series of Debt Securities or to surrender any right or power conferred upon the Company in such Indenture; (iii) to add events of default for the benefit of the holders of all or any series of Debt Securities; (iv) to add or change any provisions of the Indenture to facilitate the issuance of, or to liberalize certain terms of, Debt Securities in bearer form, or to permit or facilitate the issuance of Debt Securities in uncertificated form; provided that such action shall not adversely affect the interests of the holders of the Debt Securities in any material respect; (v) to change or eliminate any provisions of the Indenture; provided that any such change or elimination shall become effective only when there are no Debt Securities outstanding of any series created prior thereto which are entitled to the benefit of such provision; (vi) to secure the Debt Securities; (vii) to establish the form or terms of Debt Securities of any series, including the provisions and procedures, if applicable, for the conversion of such Debt Securities into Common Shares or Preferred Shares; (viii) to provide for the acceptance of appointment by a successor Indenture Trustee or facilitate the administration of the trusts under an Indenture by more than one Indenture Trustee; (ix) to cure any ambiguity, defect or inconsistency in an Indenture; provided that such action shall not adversely affect the interests of holders of Debt Securities of any series in any material respect; or (x) to supplement any of the provisions of an Indenture to the extent necessary to permit or facilitate defeasance and discharge of any series of such Debt Securities; provided that such action shall not adversely affect the interests of the holders of the Debt Securities of any series in any material respect.

        Each Indenture will provide that in determining whether the holders of the requisite principal amount of outstanding Debt Securities of a series have given any request, demand, authorization, direction, notice, consent or

7

waiver thereunder or whether a quorum is present at a meeting of holders of Debt Securities, (i) the principal amount of an Original Issue Discount Security that shall be deemed to be outstanding shall be the amount of the principal thereof that would be due and payable as of the date of such determination upon declaration of acceleration of the maturity thereof, (ii) the principal amount of a Debt Security denominated in a foreign currency that shall be deemed outstanding shall be the U.S. dollar equivalent, determined on the issue date for such Debt Security, of the principal amount (or, in the case of an Original Issue Discount Security, the U.S. dollar equivalent on the issue date of such Debt Security of the amount determined as provided in (i) above), (iii) the principal amount of an indexed security that shall be deemed outstanding shall be the principal face amount of such indexed security at original issuance, unless otherwise provided with respect to such indexed security in the applicable Indenture, and (iv) Debt Securities owned by the Company or any other obligor upon the Debt Securities or any affiliate of the Company or of such other obligor shall be disregarded.

        Each Indenture will contain provisions for convening meetings of the holders of Debt Securities of a series. A meeting may be called at any time by an Indenture Trustee, and also, upon request, by the Company or the holders of at least 25% in principal amount of the outstanding Debt Securities of such series, in any such case, upon notice given as provided in such Indenture. Except for any consent that must be given by the holder of each Debt Security affected by certain modifications and amendments of an Indenture, any resolution presented at a meeting or adjourned meeting duly reconvened at which a quorum is present may be adopted by the affirmative vote of the holders of a majority in principal amount of the outstanding Debt Securities of that series; provided, however, that, except as referred to above, any resolution with respect to any request, demand, authorization, direction, notice, consent, waiver or other action that may be made, given or taken by the holders of a specified percentage, which is less than a majority, in principal amount of the outstanding Debt Securities of a series may be adopted at a meeting or adjourned meeting duly reconvened at which a quorum is present by the affirmative vote of the holders of such specified percentage in principal amount of the outstanding Debt Securities for that series. Any resolution passed or decision taken at any meeting of holders of Debt Securities of any series duly held in accordance with the applicable Indenture will be binding on all holders of Debt Securities of that series. The quorum at any meeting called to adopt a resolution, and at any reconvened meeting, will be persons holding or representing a majority in principal amount of the outstanding Debt Securities of a series; provided, however, that if any action is to be taken at such meeting with respect to a consent or waiver which may be given by the holders of not less than a specified percentage in principal amount of the outstanding Debt Securities of a series, the persons holding or representing such specified percentage in principal amount of the outstanding Debt Securities of such series will constitute a quorum.

        Notwithstanding the foregoing provisions, each Indenture will provide that if any action is to be taken at a meeting of holders of Debt Securities of any series with respect to any request, demand, authorization, direction, notice, consent, waiver or other action that such Indenture expressly provides may be made, given or taken by the holders of such series and one or more additional series: (i) there shall be no minimum quorum requirement for such meeting and (ii) the principal amount of the outstanding Debt Securities of such series that vote in favor of such request, demand, authorization, direction, notice, consent, waiver or other action shall be taken into account in determining whether such request, demand, authorization, direction, notice, consent, waiver or other action has been made, given or taken under such Indenture.

Discharge, Defeasance and Covenant Defeasance

        The Company may discharge certain obligations to holders of any series of Debt Securities that have not already been delivered to the applicable Indenture Trustee for cancellation and that either have become due and payable or will become due and payable within one year (or scheduled for redemption within one year) by irrevocably depositing with such Indenture Trustee, in trust, funds in such currency or currencies, currency unit or units or composite currency or currencies in which such Debt Securities are payable in an amount sufficient to pay the entire indebtedness on such Debt Securities in respect of principal (and premium, if any) and interest to the date of such deposit (if such Debt Securities have become due and payable) or to the stated maturity or redemption date, as the case may be.

        An Indenture may provide that, if certain provisions thereof are made applicable to the Debt Securities of or within a series pursuant to the Indenture, the Company may elect either (i) to defease and be discharged from any and all obligations with respect to such Debt Securities (except for the obligation to pay additional amounts, if any,

8

upon the occurrence of certain events of tax, assessment or governmental charge with respect to payments on such Debt Securities and the obligations to register the transfer or exchange of such Debt Securities, to replace temporary or mutilated, destroyed, lost or stolen Debt Securities, to maintain an office or agency in respect of such Debt Securities and to hold moneys for payment in trust) ("defeasance") or (ii) to be released from its obligations with respect to such Debt Securities under certain sections of such Indenture (including the restrictions described under "—Certain Covenants") and, if provided pursuant to such Indenture, its obligations with respect to any other covenant, and any omission to comply with such obligations shall not constitute a default or an event of default with respect to such Debt Securities ("covenant defeasance"), in either case upon the irrevocable deposit by the Company with the applicable Indenture Trustee, in trust, of an amount, in such currency or currencies, currency unit or units of composite currency or currencies in which such Debt Securities are payable at stated maturity, or Government Obligations (as defined below), or both, applicable to such Debt Securities which through the scheduled payment of principal and interest, in accordance with their terms will provide money in an amount sufficient to pay the principal of (and premium, if any) and interest on such Debt Securities, and any mandatory sinking fund or analogous payments thereon, on the scheduled dates therefor.

        Such a trust may be established only if, among other things, the Company has delivered to the applicable Indenture Trustee an opinion of counsel (as specified in the applicable Indenture) to the effect that the holders of such Debt Securities will not recognize income, gain or loss for U.S. federal income tax purposes as a result of such defeasance or covenant defeasance and will be subject to U.S. federal income tax on the same amounts, in the same manner and at the same times as would have been the case if such defeasance or covenant defeasance had not occurred.

        "Government Obligations" means securities which are (i) direct obligations of the United States of America or the government which issued the foreign currency in which the Debt Securities of a particular series are payable, for the payment of which its full faith and credit is pledged or (ii) obligations of a person controlled or supervised by and acting as an agency or instrumentality of the United States of America or such government which issued the foreign currency in which the Debt Securities of a particular series are payable, the payment of which is unconditionally guaranteed as a full faith and credit obligation by the United States of America or such other government, which, in either case, are not callable or redeemable at the option of the issuer thereof, and shall also include a depository receipt issued by a bank or trust company as custodian with respect to any such Government Obligation or a specific payment of interest on or principal of any such Government Obligation held by such custodian for the account of the holder of a depository receipt; provided that (except as required by law) such custodian is not authorized to make any deduction from the amount payable to the holder of such depository receipt from any amount received by the custodian in respect of the Government Obligations or the specific payment of interest on or principal of the Government Obligations evidenced by such depository receipt.

        Unless otherwise provided in the applicable Prospectus Supplement, if after the Company has deposited funds and/or Government Obligations to effect defeasance or covenant defeasance with respect to Debt Securities of any series, (i) the holder of a Debt Security of such series is entitled to, and does, elect pursuant to the applicable Indenture or the terms of such Debt Security to receive payment in a currency, currency unit or composite currency other than that in which such deposit has been made in respect of such Debt Security, or (ii) a Conversion Event (as defined below) occurs in respect of the currency, currency unit or composite currency in which such deposit has been made, the indebtedness represented by such Debt Security shall be deemed to have been, and will be, fully discharged and satisfied through the payment of the principal of (and premium, if any) and interest on such Debt Security as they become due out of the proceeds yielded by converting the amount so deposited in respect of such Debt Security into the currency, currency unit or composite currency in which such Debt Security becomes payable as a result of such election or such cessation of usage based on the applicable market exchange rate. "Conversion Event" means the cessation of use of (i) a currency, currency unit or composite currency both by the government of the country which issued such currency and for the settlement of transactions by a central bank or other public institutions of or within the international banking community, (ii) the ECU both within the European Monetary System and for the settlement of transactions by public institutions of or within the European Communities or (iii) any currency unit or composite currency other than the ECU for the purposes for which it was established. Unless otherwise provided in the applicable Prospectus Supplement, all payments of principal of (and premium, if any) and interest on any Debt Security that is payable in a foreign currency that ceases to be used by its government of issuance shall be made in U.S. dollars.

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        In the event the Company effects covenant defeasance with respect to any Debt Securities and such Debt Securities are declared due and payable because of the occurrence of any event of default other than the event of default described in clause (d) under "—Events of Default, Notice and Waiver" with respect to certain sections of the applicable Indenture (which sections would no longer be applicable to such Debt Securities) or described in clause (g) under "—Events of Default, Notice and Waiver" with respect to any other covenant as to which there has been covenant defeasance, the amount in such currency, currency unit or composite currency in which such Debt Securities are payable, and Government Obligations on deposit with the Trustee, will be sufficient to pay amounts due on such Debt Securities at the time of their stated maturity but may not be sufficient to pay amounts due on such Debt Securities at the time of the acceleration resulting from such event of default. However, the Company would remain liable to make payment of such amounts due at the time of acceleration.

        Notwithstanding the description set forth under "—Subordination" below, in the event that the Company deposits money or Government Obligations in compliance with the applicable Indenture in order to defease all or certain of its obligations with respect to any Subordinated Securities, the moneys or Government Obligations so deposited will not be subject to the subordination provisions of such Indenture and the indebtedness evidenced by such Subordinated Securities will not be subordinated in right of payment to the holders of senior indebtedness to the extent of the moneys or Government Obligations so deposited.

        The applicable Prospectus Supplement may further describe the provisions, if any, permitting such defeasance or covenant defeasance, including any modifications to the provisions described above, with respect to the Debt Securities of or within a particular series.

Conversion Rights

        The terms and conditions, if any, upon which the Debt Securities are convertible into Common or Preferred Shares will be set forth in the Prospectus Supplement relating thereto. Such terms will include whether such Debt Securities are convertible into Common or Preferred Shares, the conversion price (or manner of calculation thereof), the conversion period, provisions as to whether conversion will be at the option of the holders of the Company, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption of such Debt Securities and any restrictions on conversion, including restrictions directed at maintaining the Company's REIT status.

Subordination

        The terms and conditions, if any, upon which Subordinated Securities of a series are subordinated to Debt Securities of other series or to other indebtedness of the Company will be set forth in the applicable Prospectus Supplement. Such terms will include a description of the indebtedness ranking senior to such Subordinated Securities, the restrictions on payments to the holders of such Subordinated Securities while a default with respect to such senior indebtedness is continuing, the restrictions, if any, on payments to the holders of such Subordinated Securities following an Event of Default, and provisions requiring holders of such Subordinated Securities to remit certain payments to holders of senior indebtedness.

Global Securities

        If so set forth in the applicable Prospectus Supplement, the Debt Securities of a series may be issued in whole or in part in the form of one or more Global Securities that will be deposited with, or on behalf of, a depositary identified in the applicable Prospectus Supplement relating to such series. Global Securities may be issued in either registered or bearer form and in either temporary or permanent form. The specific terms of the depositary arrangement with respect to any such series of Debt Securities will be described in the applicable Prospectus Supplement.

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DESCRIPTION OF SHARES

        The Declaration of Trust ("Declaration") authorizes the Company to issue an aggregate of 200,000,000 shares of beneficial interest ("Shares") in the Company, including (i) 150,000,000 Common Shares, par value $.01 per share, and (ii) 50,000,000 Preferred Shares, par value $.01 per share. The Declaration permits the Trustees to amend the Declaration to increase or decrease the authorized Shares of the Company without the requirement of shareholder approval.

        The Declaration authorizes the Trustees, without shareholder approval, from time to time to divide the Preferred Shares into classes or series and to set (or change, if the class or series has been previously established) the par value, if any, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends, qualifications or terms and conditions of redemption of such Preferred Shares as are not prohibited by the Declaration or applicable law. In connection with the adoption of the Company's shareholders rights plan (see "Redemption; Business Combinations and Control Share Acquisitions—Rights Plan," below), the Trustees established an authorized but unissued class of 1,500,000 Preferred Shares, par value $.01 per share (the "Junior Participating Preferred Shares"), described more fully below under "Description of Preferred Shares—Junior Participating Preferred Shares," and as of June 2, 1998 no other class or series of Preferred Shares had been established.

        As of June 2, 1998 there were 131,532,678 Shares outstanding, all of which were Common Shares. The Company also had outstanding as of such date $204.9 million aggregate principal amount convertible subordinated debentures of various series, all of which are convertible into Common Shares at an exercise price equal on such date to $18 per share. See "Description of Convertible Subordinated Debentures."

        The following descriptions do not purport to be complete and are subject to, and qualified in their entirety by reference to, the more complete descriptions thereof set forth in the Declaration. Capitalized terms not defined herein are as defined in the Declaration.

        Except as otherwise determined by the Trustees with respect to any class or series of Preferred Shares, all Shares: (i) will participate equally in dividends payable to shareholders when, as and if declared by the Trustees and ratably in net assets available for distribution to shareholders on liquidation or dissolution; (ii) will have one vote per share on all matters submitted to a vote of the shareholders, (iii) will not have cumulative voting rights in the election of Trustees; and (iv) will have no preference, conversion, exchange, sinking fund, redemption rights or preemptive or similar rights.

        Upon issuance in accordance with the Declaration, applicable law and the terms and conditions described in the related Prospectus Supplement, the Shares will be fully paid and nonassessable. The holders of Shares do not have preemptive rights with respect to the issuance of additional Shares or other securities of the Company.

        The authorized but unissued Shares will be available for issuance from time to time by the Company at the sole discretion of the Trustees for any proper trust purpose, which could include raising capital, providing compensation or benefits to employees and others, paying stock dividends or acquiring companies, businesses or properties. The issuance of such unissued Shares could have the effect of diluting the earnings per share and book value per share of currently outstanding Shares.

        For certain other information with respect to the Shares, see "Limitation of Liabilities; Shareholder Liability" and "Redemption; Business Combinations and Control Share Acquisitions" below.

        The Transfer Agent and Registrar for the Company's Shares is State Street Bank and Trust Company, c/o Boston EquiServe, P.O. Box 8200, Boston, Massachusetts 02266-8200 (telephone number (800) 426-5523).


DESCRIPTION OF PREFERRED SHARES

        The Declaration authorizes the Trustees, without shareholder approval, from time to time to divide the Preferred Shares into classes or series and to set (or change, if the class or series has been previously established) the par value, if any, preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends, qualifications or terms and conditions of redemption of such Preferred Shares that are not prohibited by the Declaration or applicable law.

        The following description of the Preferred Shares sets forth certain general terms and provisions of the Preferred Shares to which any Prospectus Supplement may relate and a brief summary of certain terms of the

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Company's Junior Participating Preferred Shares. The statements below describing the Preferred Shares are in all respects subject to and qualified in their entirety by reference to the applicable provisions of the Declaration (including any applicable articles supplementary) and By-Laws.

General

        Subject to limitations prescribed by Maryland law and the Declaration, the Trustees are authorized to fix the number of shares constituting each series of Preferred Shares and the designations and powers, preferences and relative, participating, optional or other specific rights and qualifications, limitations or restrictions thereof, including such provisions as may be desired concerning voting, redemption, dividends, dissolution or the distribution of assets, conversion or exchange, and such other subjects or matters as may be fixed by resolutions of the Trustees.

        Reference is made to the Prospectus Supplement relating to the Preferred Shares offered thereby for specific terms, including:

        As described under "Description of Depositary Shares," the Company may, at its option, elect to offer Depositary Shares evidenced by depositary receipts ("Depositary Receipts"), each representing a fractional interest (to be specified in the Prospectus Supplement relating to the particular series of the Preferred Shares) in a share of the particular series of the Preferred Shares issued and deposited with a Depositary (as defined below).

Rank

        Unless otherwise determined by the Trustees and specified in the applicable Prospectus Supplement, it is expected that the Preferred Shares will, with respect to dividend rights and rights upon liquidation, dissolution or winding up of the Company, rank (i) senior to all Common Shares, and to all equity securities ranking junior to such Preferred Shares; (ii) on a parity with all equity securities issued by the Company the terms of which specifically provide that such equity securities rank on a parity with the Preferred Shares; and (iii) junior to all

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equity securities issued by the Company the terms of which specifically provide that such equity securities rank senior to the Preferred Shares.

Dividends

        Holders of Preferred Shares of each series shall be entitled to receive, when, as and if declared by the Trustees, out of assets of the Company legally available for payment, cash dividends at such rates and on such dates as will be set forth in the applicable Prospectus Supplement. Each such dividend shall be payable to holders of record as they appear on the stock transfer books of the Company (or, if applicable, on the records of the Depositary referred to below under "Description of Depositary Shares") on such record dates as shall be fixed by the Trustees.

        Dividends on any series of the Preferred Shares may be cumulative or noncumulative, as provided in the applicable Prospectus Supplement. Dividends, if cumulative, will be cumulative from and after the date set forth in the applicable Prospectus Supplement. If the Trustees fail to declare a dividend payable on a dividend payment date on any series of the Preferred Shares for which dividends are noncumulative, then the holders of such series of the Preferred Shares will have no right to receive a dividend in respect of the dividend period ending on such dividend payment date, and the Company will have no obligation to pay the dividend accrued for such period, whether or not dividends on such series are declared payable on any future dividend payment date.

        If Preferred Shares of any series are outstanding, no full dividends shall be declared or paid or set apart for payment on the Preferred Shares of the Company of any other series ranking, as to dividends, on a parity with or junior to the Preferred Shares of such series for any period unless (i) if such series of Preferred Shares has a cumulative dividend, full cumulative dividends have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for such payment on the Preferred Shares of such series for all past dividend periods and the then current dividend period or (ii) if such series of Preferred Shares does not have a cumulative dividend, full dividends for the then current dividend period have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for such payment on the Preferred Shares of such series. When dividends are not paid in full (or a sum sufficient for such full payment is not so set apart) upon the Preferred Shares of any series and the shares of any other series of Preferred Shares ranking on a parity as to dividends with the Preferred Shares of such series, all dividends declared upon Preferred Shares of such series and any other series of Preferred Shares shall in all cases bear to each other the same ratio that accrued dividends per share on the Preferred Shares of such series (which shall not include any accumulation in respect of unpaid dividends for prior dividend periods if such Preferred Shares do not have a cumulative dividend) and such other series of Preferred Shares bear to each other. No interest, or sum of money in lieu of interest, shall be payable in respect of any dividend payment or payments on Preferred Shares of such series which may be in arrears.

        Except as provided in the immediately preceding paragraph, unless (i) if such series of Preferred Shares has a cumulative dividend, full cumulative dividends on the Preferred Shares of such series have been or contemporaneously are declared and paid or declared and a sum sufficient for the repayment thereof set apart for payment for all past dividend periods and the then current dividend period, and (ii) if such series of Preferred Shares does not have a cumulative dividend, full dividends on the Preferred Shares of such series have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for the then current dividend period, no dividends (other than in Common Shares or other capital stock ranking junior to the Preferred Shares of such series as to dividends and upon liquidation) shall be declared or paid or set aside for payment or other distribution shall be declared or made upon the Common Shares or any other capital stock of the Company ranking junior to or on a parity with the Preferred Shares of such series as to dividends or upon liquidation, nor shall any Common Shares or any other capital stock of the Company ranking junior to or on a parity with the Preferred Shares of such series as to dividends or upon liquidation be redeemed, purchased or otherwise acquired for any consideration (or any moneys be paid to or made available for a sinking fund for the redemption of any shares of any such stock) by the Company (except by conversion into or exchange for other capital stock of the Company ranking junior to the Preferred Shares of such series as to dividends and upon liquidation and except pursuant to certain pro rata offers to purchase or a concurrent redemption of all, or a pro rata portion of, the outstanding shares of the Preferred Shares of such series and any other series of Preferred Shares ranking on a parity with such series as to dividends and liquidation).

        Any dividend payment made on shares of a series of Preferred Shares shall first be credited against the earliest accrued but unpaid dividend due with respect to shares of such series which remains payable.

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Redemption

        If so provided in the applicable Prospectus Supplement, the Preferred Shares will be subject to mandatory redemption or redemption at the option of the Company, as a whole or in part, in each case upon the terms, at the times and at the redemption prices set forth in such Prospectus Supplement.

        The Prospectus Supplement relating to a series of Preferred Shares that is subject to mandatory redemption will specify the number of such Preferred Shares that shall be redeemed by the Company in each year commencing after a date to be specified, at a redemption price per share to be specified, together with an amount equal to all accrued and unpaid dividends thereon (which shall not, if such Preferred Shares do not have a cumulative dividend, include any accumulation in respect of unpaid dividends for prior dividend periods) to the date of redemption. The redemption price may be payable in cash or other property, as specified in the applicable Prospectus Supplement. If the redemption price for Preferred Shares of any series is payable only from the net proceeds of the issuance of capital stock of the Company, the terms of such Preferred Shares may provide that, if no such capital stock shall have been issued or to the extent the net proceeds from any issuance are insufficient to pay in full the aggregate redemption price then due, such Preferred Shares shall automatically and mandatorily be converted into shares of the applicable capital stock of the Company pursuant to conversion provisions specified in the applicable Prospectus Supplement.

        Notwithstanding the foregoing, unless (i) if such series of Preferred Shares has a cumulative dividend, full cumulative dividends on all shares of any series of Preferred Shares shall have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for all past dividend periods and the then current dividend period, and (ii) if such series of Preferred Shares does not have a cumulative dividend, full dividends on the Preferred Shares of any series have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for the then current dividend period, no shares of any series of Preferred Shares shall be redeemed unless all outstanding Preferred Shares of such series are simultaneously redeemed; provided, however, that the foregoing shall not prevent the purchase or acquisition of Preferred Shares of such series pursuant to a purchase or exchange offer made on the same terms to holders of all outstanding Preferred Shares of such series, and, unless (i) if such series of Preferred Shares has a cumulative dividend, full cumulative dividends on all outstanding shares of any series of Preferred Shares have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for all past dividend periods and the then current dividend period, and (ii) if such series of Preferred Shares does not have a cumulative dividend, full dividends on the Preferred Shares of any series have been or contemporaneously are declared and paid or declared and a sum sufficient for the payment thereof set apart for payment for the then current dividend period, the Company shall not purchase or otherwise acquire directly or indirectly any Preferred Shares of such series (except by conversion into or exchange for capital stock of the Company ranking junior to the Preferred Shares of such series as to dividends and upon liquidation).

        If fewer than all of the outstanding Preferred Shares of any series are to be redeemed, the number of Preferred Shares to be redeemed will be determined by the Company and such shares may be redeemed pro rata from the holders of record of such shares in proportion to the number of such shares held by such holders (with adjustments to avoid redemption of fractional shares) or by lot in manner determined by the Company.

        Notice of redemption will be mailed at least 30 days but not more than 60 days before the redemption date to each holder of record of Preferred Shares of any series to be redeemed at the address shown on the stock transfer books of the Company. Each notice shall state: (i) the redemption date; (ii) the number of shares and series of the Preferred Shares to be redeemed; (iii) the redemption price; (iv) the place or places where certificates for such Preferred Shares are to be surrendered for payment of the redemption price; (v) that dividends on the shares to be redeemed will cease to accrue on such redemption date; and (vi) the date upon which the holder's conversion rights, if any, as to such shares shall terminate. If fewer than all the Preferred Shares of any series are to be redeemed, the notice mailed to each such holder thereof shall also specify the number of Preferred Shares to be redeemed from each such holder. If notice of redemption of any Preferred Shares has been given and if the funds necessary for such redemption have been set aside by the Company in trust for the benefit of the holders of any of the Preferred Shares so called for redemption, then from and after the redemption date dividends will cease to accrue on such Preferred Shares, and any and all rights of the holders of such shares will terminate, except the right to receive the redemption price.

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Liquidation Preference

        Upon any voluntary or involuntary liquidation, dissolution or winding up of the affairs of the Company, then, before any distribution or payment shall be made to the holders of any Common Shares or any other class or series of capital stock of the Company ranking junior to the Preferred Shares in the distribution of assets upon any liquidation, dissolution or winding up of the Company, the holders of each series of Preferred Shares shall be entitled to receive out of assets of the Company legally available for distribution to shareholders liquidating distributions in the amount of the liquidation preference per share (set forth in the applicable Prospectus Supplement), plus an amount equal to all dividends accrued and unpaid thereon (which shall not include any accumulation in respect of unpaid dividends for prior dividend periods if such Preferred Shares do not have a cumulative dividend). After payment of the full amount of the liquidating distributions to which they are entitled, the holders of Preferred Shares will have no right or claim to any of the remaining assets of the Company. In the event that upon any such voluntary or involuntary liquidation, dissolution or winding up, the available assets of the Company are insufficient to pay the amount of the liquidating distributions on all outstanding Preferred Shares and the corresponding amounts payable on all shares of other classes or series of capital stock of the Company ranking on a parity with the Preferred Shares in the distribution of assets, then the holders of the Preferred Shares and all other such classes or series of capital stock shall share ratably in any such distribution of assets in proportion to the full liquidating distributions to which they would otherwise be respectively entitled.

        If liquidating distributions shall have been made in full to all holders of Preferred Shares, the remaining assets of the Company shall be distributed among the holders of any other classes or series of capital stock ranking junior to the Preferred Shares upon liquidation, dissolution or winding up, according to their respective rights and preferences and in each case according to their respective number of shares. For such purposes, the consolidation or merger of the Company with or into any other trust or corporation, or the sale, lease or conveyance of all or substantially all of the property or business of the Company, shall not be deemed to constitute a liquidation, dissolution or winding up of the Company.

Voting Rights

        Holders of the Preferred Shares will not have any voting rights, except as set forth below or as otherwise from time to time required by law or as indicated in the applicable Prospectus Supplement.

        Unless otherwise specified in the related Prospectus Supplement, at any time dividends on any Preferred Shares shall be in arrears for six consecutive quarterly periods, the holders of such Preferred Shares (voting separately as a class with all other series of preferred shares upon which like voting rights have been conferred and are exercisable) will be entitled to vote for the election of two additional trustees of the Company at the next annual meeting of shareholders and at each subsequent meeting until (i) if such series of Preferred Shares has a cumulative dividend, all dividends accumulated on such Preferred Shares for the past dividend periods and the then current dividend period shall have been fully paid or declared and a sum sufficient for the payment thereof set aside for payment or (ii) if such series of Preferred Shares does not have a cumulative dividend, four consecutive quarterly dividends shall have been fully paid or declared and a sum sufficient for the payment thereof set aside for payment. In such case, the entire Trustees of the Company will be increased by two trustees.

        Unless provided otherwise for any series of Preferred Shares, so long as any Preferred Shares remain outstanding, the Company shall not, without the affirmative vote or consent of the holders of a majority of the shares of each series of Preferred Shares outstanding at the time, given in person or by proxy, either in writing or at a meeting (such series voting separately as a class), (i) authorize or create, or increase the authorized or issued amount of, any class or series of capital stock ranking prior to such series of Preferred Shares with respect to payment of dividends or the distribution of assets upon liquidation, dissolution or winding up, or reclassify any authorized capital stock of the Company into any such shares, or create, authorize or issue any obligation or security convertible into or evidencing the right to purchase any such shares; or (ii) amend, alter or repeal the provisions of the Declaration or the certificate of designations for such series of Preferred Shares, whether by merger, consolidation or otherwise, so as to materially and adversely affect any right, preference, privilege or voting power of such series of Preferred Shares or the holders thereof; provided, however, that any increase in the amount of the authorized Preferred Shares or the creation or issuance of any other series of Preferred Shares, or any increase in the amount of authorized shares of such series or any other series of Preferred Shares, in each case ranking on a parity with or junior to the Preferred Shares of such series with respect to payment of dividends or the

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distribution of assets upon liquidation, dissolution or winding up, shall not be deemed to materially and adversely affect such rights, preferences, privileges or voting powers.

        The foregoing voting provisions will not apply if, at or prior to the time when the act with respect to which such vote would otherwise be required shall be effected, all outstanding shares of such series of Preferred Shares shall have been redeemed or called for redemption and sufficient funds shall have been deposited in trust to effect such redemption.

        As more fully described under "Description of Depositary Shares" below, if the Company elects to issue Depositary Shares, each representing a fraction of a share of a series of the Preferred Shares, each such Depositary will, in effect be entitled to such fraction of a vote per Depositary Share.

Conversion Rights

        The terms and conditions, if any, upon which shares of any series of Preferred Shares may be converted into or exchanged for Common Shares or another series of Preferred Shares or other series of Offered Securities will be set forth in the Prospectus Supplement relating thereto. Such terms will include the number of Common Shares or other securities into which the Preferred Share is convertible or exchangeable, conversion or exchange price (or manner of calculation thereof), the conversion or exchange period, provisions as to whether conversion or exchange will be at the option of the holders of the Preferred Shares or the Company, the events requiring an adjustment of the conversion or exchange price and provisions affecting conversion or exchange in the event of the redemption such Preferred Shares.

Junior Participating Preferred Shares

        In connection with the adoption of the Company's shareholders rights plan, the Trustees established an authorized but unissued class of 1,500,000 Preferred Shares. See "Redemption; Business Combinations and Control Share Acquisitions" below. Certain powers, preferences and rights and certain qualifications, limitations and restrictions of the Junior Participating Preferred Shares, when and if issued, are as follows. The statements below with respect to the Junior Participating Preferred Shares are in all respects subject to and qualified in their entirety by reference to the applicable provisions of the Declaration (including the applicable articles supplementary) and By-Laws.

        The holder of each Junior Participating Preferred Share is entitled to quarterly dividends in the greater amount of $5.00 or 100 times the quarterly per share dividend, whether cash or otherwise, declared upon the Common Shares. Dividends on the Junior Participating Preferred Shares are cumulative. Whenever dividends on the Junior Participating Preferred Shares are in arrears, the Company, among other things, is prohibited from declaring or paying dividends, making other distributions on, or redeeming or repurchasing Common Shares or other Shares ranking junior to the Junior Participating Preferred Shares, and upon failure of the Company to pay such dividends for six quarters, the holders of the Junior Participating Preferred Shares will be entitled to elect two Trustees. The holder of each Junior Participating Preferred Share is entitled to 100 votes on all matters submitted to a vote of the shareholders, voting (unless otherwise provided in the Declaration or by law) together with holders of Common Shares as one class. Upon liquidation, dissolution or winding up of the Company, the holders of Junior Participating Preferred Shares are entitled to a liquidation preference of $100 per share plus the amount of any accrued and unpaid dividends and distributions thereon (the "Liquidation Preference"), prior to payment of any distribution in respect of the Common Shares or any other Shares ranking junior to the Junior Participating Preferred Shares. Following payment of the Liquidation Preference, the holders of Junior Participating Preferred Shares are not entitled to further distributions until the holders of Common Shares shall have received an amount per share (the "Common Share Adjustment") equal to the Liquidation Preference divided by 100 (adjusted to reflect events such as stock splits, stock dividends and recapitalizations affected the Common Shares) (the "Adjustment Number"). Following the payment of the full amount of the Liquidation Preference and the Common Share Adjustment, holders of Junior Participating Preferred Shares are entitled to participate proportionately on a per share basis with holders of Common Shares in the distribution of the remaining assets to be distributed in respect of Shares in the ratio of the Adjustment Number to one, respectively. The powers, preferences and rights of the Junior Participating Preferred Shares are subject to the superior powers, preferences and rights of any senior series or class of Preferred Shares which the Trustees shall, from time to time, authorize and issue.

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DESCRIPTION OF DEPOSITARY SHARES

General

        The description set forth below and in any applicable Prospectus Supplement of certain provisions of any Deposit Agreement (as defined below) and of the Depositary Shares and depositary receipts representing Depositary Shares ("Depositary Receipts") does not purport to be complete and is subject to and qualified in its entirety by reference to the forms of Deposit Agreement and Depositary Receipts relating to each series of the Preferred Shares which have been or will be filed with the Commission at or prior to the time of the offering of such series of the Preferred Shares.

        The Company may, at its option, elect to offer fractional interests in shares of Preferred Shares, rather than shares of Preferred Shares. In the event such option is exercised, the Company will provide for the issuance by a Depositary (as defined below) to the public of receipts for Depositary Shares, each of which will represent a fractional interest to be set forth in the Prospectus Supplement relating to a particular series of the Preferred Shares which will be filed with the Commission at or prior to the time of the offering of such series of the Preferred Shares as described below. Preferred Shares of each series represented by Depositary Shares will be deposited under a separate deposit agreement (each, a "Deposit Agreement") among the Company and the depositary named therein (a "Depositary"). The Prospectus Supplement relating to a series of Depositary Shares will set forth the name and address of the Depositary. Subject to the terms of the applicable Deposit Agreement, each owner of a Depositary Share will be entitled, in proportion to the fractional interest of a share of a particular series of Preferred Shares represented by such Depositary Share to all the rights and preferences of the Preferred Shares represented by such Depositary Shares (including dividend, voting, conversion, redemption and liquidation rights).

        The Depositary Shares will be evidenced by Depositary Receipts issued pursuant to the applicable Deposit Agreement. Upon surrender of Depositary Receipts at the office of the Depositary and upon payment of the charges provided in the Deposit Agreement and subject to the terms thereof, a holder of Depositary Shares is entitled to have the Depositary deliver to such holder the whole shares of Preferred Shares underlying the Depositary Shares evidenced by the surrendered Depositary Receipts.

Dividends and Other Distributions

        A Depositary will be required to distribute all cash dividends or other cash distributions received in respect of the applicable Preferred Shares to the record holders of Depositary Receipts evidencing the related Depositary Shares in proportion to the number of such Depositary Receipts owned by such holders, subject to certain obligations of holders to file proofs, certificates and other information and to pay certain charges and expenses to such Depositary. Fractions will be rounded down to the market whole cent.

        In the event of a distribution other than in cash, a Depositary will be required to distribute property received by it to the record holders of Depositary Receipts entitled thereto, subject to certain obligations of holders to file proofs, certificates and other information and to pay certain charges and expenses to such Depositary, unless such Depositary determines that it is not feasible to make such distribution, in which case such Depositary may, with the approval of the Company, sell such property and distribute the net proceeds from such sale to such holders.

        No distributions will be made in respect of any Depositary Share to the extent that it represents any Preferred Shares which have been converted or exchanged. The Deposit Agreement will also contain provisions relating to the manner in which any subscription or similar rights offered by the Company to holders of the Preferred Shares shall be made available to holders of Depositary Shares.

Redemption of Depositary Shares

        If a series of the Preferred Shares underlying the Depositary Shares is subject to redemption, the Depositary Shares will be redeemed from the proceeds received by the Depositary resulting from the redemption, in whole or in part, of such series of the Preferred Shares held by the Depositary. The Depositary shall mail notice of redemption not less than 30 and not more than 60 days prior to the date fixed for redemption to the record holders of the Depositary Receipts evidencing the Depositary Shares to be so redeemed at their respective addresses appearing in the Depositary's books. The redemption price per Depositary Share will be equal to the applicable fraction of the redemption price per share payable with respect to such series of the Preferred Shares. Whenever

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the Company redeems shares of Preferred Shares held by the Depositary, the Depositary will redeem as of the same redemption date the number of Depositary Shares relating to shares of Preferred Shares so redeemed. If less than all of the Depositary Shares are to be redeemed, the Depositary Shares to be redeemed will be selected by lot or pro rata as may be determined by the Depositary.

        After the date fixed for redemption, the Depositary Shares so called for redemption will no longer be deemed to be outstanding and all rights of the holders of the Depositary Shares and the related Depositary Receipts will cease, except the right to receive the moneys payable upon such redemption and any money or other property to which the holders of such Depositary Shares were entitled upon such redemption upon surrender to the Depositary of the Depositary Receipts evidencing such Depositary Shares.

Voting of the Preferred Shares

        Upon receipt of notice of any meeting at which the holders of the applicable Preferred Shares are entitled to vote, a Depositary will be required to mail the information contained in such notice of meeting to the record holders of the Depositary Receipts evidencing the Depositary Shares which represent such Preferred Shares. Each record holder of Depositary Receipts evidencing Depositary Shares on the record date (which will be the same date as the record date for the Preferred Shares) will be entitled to instruct such Depositary as to the exercise of the voting rights pertaining to the amount of Preferred Shares represented by such holder's Depositary Shares. Such Depositary will endeavor, insofar as practical, to vote the amount of Preferred Shares represented by such Depositary Shares in accordance with such instructions, and the Company will agree to take all reasonable action which may be deemed necessary by such Depositary in order to enable such Depositary to do so. Such Depositary will be required to abstain from voting the amount of Preferred Shares represented by such Depositary Shares to the extent it does not receive specific instructions from the holders of Depositary Receipts evidencing such Depositary Shares. The Depositary will not be responsible for any failure to carry out any instruction to vote, or for the manner or effect of any such vote made, as long as such action or non-action is in good faith and does not result from gross negligence or willful misconduct of such Depositary.

Liquidation Preference

        In the event of the liquidation, dissolution or winding up of the Company, whether voluntary or involuntary, the holders of each Depositary Share will be entitled to the fraction of the liquidation preference accorded each Preferred Share represented by such Depositary Share, as set forth in the applicable Prospectus Supplement.

Conversion of Preferred Shares

        The Depositary Shares, as such, will not be convertible into or exchangeable for Common Shares, Preferred Shares or any other securities or property of the Company. Nevertheless, if so specified in the applicable Prospectus Supplement relating to an offering of Depositary Shares, the Depositary Receipts may be surrendered by holders thereof to the applicable Depositary with written instructions to such Depositary to instruct the company to cause conversion or exchange of the Preferred Shares represented by the Depositary Shares evidenced by such Depositary Receipts into Common Shares, other shares of Preferred Shares of the Company or such other securities as shall be provided therein, and the Company will agree that upon receipt of such instruction and any amounts payable in respect thereof, it will cause the conversion or exchange thereof utilizing the same procedures as those provided for delivery of Preferred Shares to effect such conversion or exchange. If the Depositary Shares evidenced by a Depositary Receipt are to be converted in part only, a new Depositary Receipt or Depositary Receipts will be issued for any Depositary Shares not to be converted.

Amendment and Termination of a Deposit Agreement

        Any form of Depositary Receipt evidencing Depositary Shares and any provision of a Deposit Agreement will be permitted at any time to be amended by agreement between the Company and the applicable Depositary. However, any amendment that materially and adversely alters the rights of the holders of Depositary Shares will not be effective unless such amendment has been approved by the existing holders of at least a majority of the applicable Depositary Shares then outstanding. Every holder of an outstanding Depositary Receipt at the time any

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such amendment becomes effective shall be deemed, by continuing to hold such Depositary Receipt, to consent and agree to such amendment and to be bound by the applicable Deposit Agreement as amended thereby.

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

Charges of a Depositary

        The Company will pay all transfer and other taxes and governmental charges arising solely from the existence of a Deposit Agreement. In addition, the Company will pay the fees and expenses of a Depositary in connection with the initial deposit of the Preferred Shares and any redemption of Preferred Shares. However, holders of Depositary Receipts will pay any transfer or other governmental charges and the fees and expenses of a Depositary for any duties requested by such holders to be performed which are outside of those expressly provided for in the applicable Deposit Agreement.

Resignation and Removal of Depositary

        A Depositary may resign at any time by delivering to the Company notice of its election to do so, and the Company may at any time remove a Depositary, any such resignation or removal to take effect upon the appointment of a successor Depositary. A successor Depositary will be required to be appointed within 60 days after delivery of the notice of resignation or removal and will be required to be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50 million.

Miscellaneous

        A Depositary will be required to forward to holders of Depositary Receipts any reports and communications from the Company which are received by such Depositary with respect to the related Preferred Shares.

        Neither Depositary nor the Company will be liable if it is prevented from or delayed in, by law or any circumstances beyond its control, performing its obligations under a Deposit Agreement. The obligations of the Company and a Depositary under a Deposit Agreement will be limited to performing their duties thereunder in good faith and without gross negligence or willful misconduct, and neither the Company nor any applicable Depositary will be obligated to prosecute or defend any legal proceeding in respect of any Depositary Receipts, Depositary Shares or Preferred Shares represented thereby unless satisfactory indemnity is furnished. The Company and any Depositary will be permitted to rely on written advice of counsel or accountants, on information provided by persons presenting Preferred Shares represented thereby for deposit, holders of Depositary Receipts or other persons believed in good faith to be competent to give such information, and on documents believed in good faith to be genuine and signed by a proper party.

        In the event a Depositary shall receive conflicting claims, requests or instructions from any holders of Depositary Receipts, on the one hand, and the Company, on the other hand, such Depositary shall be entitled to act on such claims, requests or instructions received from the Company.

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DESCRIPTION OF WARRANTS

        The Company may issue, together with any other series of Offered Securities or separately, Warrants entitling the holder to purchase from or sell to the Company, or to receive from the Company the cash value of the right to purchase or sell, Debt Securities, Preferred Shares, Depositary Shares or Common Shares. The Warrants are to be issued under Warrant Agreements (each a "Warrant Agreement") to be entered into between the Company and a warrant agent (the "Warrant Agent"), all as set forth in the applicable Prospectus Supplement relating to the particular issue of Warrants.

        In the case of each series of Warrants, the applicable Prospectus Supplement will describe the terms of the Warrants being offered thereby, including the following, if applicable: (i) the offering price; (ii) the currencies in which such Warrants are being offered; (iii) the number of Warrants offered; (iv) the securities underlying the Warrants; (v) the exercise price, the procedures for exercise of the Warrants and the circumstances, if any, that will cause the Warrants to be deemed to be automatically exercised; (vi) the date on which the right shall expire; (vii) U.S. federal income tax consequences; and (viii) other terms of the Warrants.

        Warrants may be exercised at the appropriate office of the Warrant Agent or any other office indicated in the applicable Prospectus Supplement. Prior to the exercise of Warrants entitling the holder to purchase any securities, holders of such Warrants will not have any of the rights of holders of the securities purchasable upon such exercise and will not be entitled to payments made to holders of such securities.

        The Warrant Agreements may be amended or supplemented without the consent of the holders of the Warrants issued thereunder to effect changes that are not inconsistent with the provisions of the Warrants and that do not adversely affect the interests of the holders of the Warrants.


DESCRIPTION OF CONVERTIBLE SUBORDINATED DEBENTURES

        In October 1996 the Company issued $240 million aggregate principal amount of convertible subordinated debentures (the "Convertible Subordinated Debentures"), consisting of $70 million aggregate principal amount of 7.5% Convertible Subordinated Debentures due 2003, Series A (the "Series A Debentures"), $130 million aggregate principal amount of 7.5% Convertible Subordinated Debentures due 2003, Series B (the "Series B Debentures"), and $40 million aggregate principal amount of 7.25% Convertible Subordinated Debentures due 2001 (the "7.25% Debentures"). The Series A Debentures and the 7.25% Debentures were sold in offerings registered under the Securities Act, and the Series B Debentures were sold in an offering outside of the United States pursuant to Regulation S promulgated under the Securities Act.

        The Convertible Subordinated Debentures are convertible into Common Shares, initially at a conversion price of $18 per Common Share, at any time prior to maturity or earlier redemption. Such conversion price is subject to adjustment in certain events, including the payment of dividends or distributions on the Company's Shares in Common Shares or certain other securities issued by the Company, the issuance to all holders of Common Shares of rights, options or warrants entitling them to subscribe for Common Shares (or securities convertible into Common Shares), subdivisions or combinations of the Common Shares into a greater or smaller number of shares, reclassification of Common Shares resulting in an issuance of any of the Company's Shares and certain mergers or combination or sales of substantially all assets of the Company.

        As of June 2, 1998 $35.1 million in principal amount of the Series A and Series B Debentures had been converted into an aggregate of 2.0 million Common Shares, and none of the 7.25% Debentures had been converted.

        The indebtedness evidenced by the Convertible Subordinated Debentures is subordinated and junior in right of payment, to the extent set forth in the trust indenture applicable thereto, to the prior payment in full of amounts then due in respect of all indebtedness of the Company for borrowed money and certain other indebtedness, excluding (i) indebtedness of the Company to a subsidiary or an officer, director, trustee or employee of the Company or a subsidiary, (ii) indebtedness of the Company which, pursuant to the terms of the instrument creating or evidencing such indebtedness, is expressly made pari passu with or subordinate in right of payment to the Convertible Subordinated Debentures and (iii) any liability of the Company for taxes.

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        The preceding discussion of certain terms of the Convertible Subordinated Debentures is a summary of certain provisions of the Convertible Subordinated Debentures and the related trust indenture. Such discussion does not purport to be complete and is in all respects subject to and qualified in its entirety by reference to the complete terms thereof and of such trust indenture.


LIMITATION OF LIABILITY; SHAREHOLDER LIABILITY

        Maryland law permits a REIT to provide, and the Declaration provides, that no trustee, officer, shareholder, employee or agent of the Company shall be held to any personal liability, jointly or severally, for any obligation of or claim against the Company, and that, as far as practicable, each written agreement of the Company is to contain a provision to that effect. Despite these facts, counsel has advised the Company that in some jurisdictions the possibility exists that shareholders of a non-corporate entity such as the Company may be held liable for acts or obligations of the Company. Counsel has advised the Company that the State of Texas may not give effect to the limitation of shareholder liability afforded by Maryland law, but that Texas law would likely recognize contractual limitations of liability such as those discussed above. The Company intends to conduct its business in a manner designed to minimize potential shareholder liability by, among other things, inserting appropriate provisions in written agreements of the Company; however, no assurance can be given that shareholders can avoid liability in all instances in all jurisdictions.

        The Declaration provides that, upon payment by a shareholder of any such liability, the shareholder will be entitled to indemnification by the Company. There can be no assurance that, at the time any such liability arises, there will be assets of the Company sufficient to satisfy the Company's indemnification obligation. The Trustees intend to conduct the operations of the Company, with the advice of counsel, in such a way as to minimize or avoid, as far as practicable, the ultimate liability of the shareholders of the Company. The Trustees do not intend to provide insurance covering such risks to the shareholders.


REDEMPTION; BUSINESS COMBINATIONS AND CONTROL SHARE ACQUISITIONS

Redemption and Business Combinations

        For the Company to qualify as a REIT under the Code, in any taxable year, not more than 50% in value of its outstanding Shares may be owned, directly or indirectly by five or fewer individuals during the last six months of such year, and the shares must be owned by 100 or more persons during at least 335 days of a taxable year or a proportionate part of a taxable year less than 12 months. In order to meet these and other requirements, the Trustees have the power to redeem or prohibit the transfer of a sufficient number of Shares to maintain or bring the ownership of the Shares into conformity with such requirements. In connection with the foregoing, if the Trustees shall, at any time and in good faith, be of the opinion that direct or indirect ownership of shares representing more than 8.5% in value of the total Shares outstanding (the "Excess Shares") has or may become concentrated in the hands of one beneficial owner, other than Excepted Persons, the Trustees shall have the power (i) to purchase from any shareholder of the Company such Excess Shares, and (ii) to refuse to transfer or issue Shares to any person whose acquisition of such Shares would, in the opinion of the Trustees, result in the direct or indirect beneficial ownership by any person of Shares representing more than 8.5% in value of the outstanding Shares. Any transfer of Shares, options, or other securities convertible into Shares that would create a beneficial owner (other than any of the Excepted Persons) of Shares representing more than 8.5% in value of the total Shares outstanding shall be deemed void ab initio, and the intended transferee shall be deemed never to have had an interest therein. Further the Declaration provides that transfers or purported acquisitions, directly, indirectly or by attribution, of Shares, or securities convertible into Shares, that could result in disqualification of the Company as a REIT are null and void and permits the Trustees to repurchase Shares or other securities to the extent necessary to maintain the Company's status as a REIT. The purchase price for any Shares so purchased shall be determined by the price of the Shares on the principal exchange on which they are then traded, or if no such price is available, then the purchase price shall be equal to the net asset value of such Shares as determined by the Trustees in accordance with applicable law. From and after the date fixed for purchase by the Trustees, and so long as payment of the purchase price for the Shares to be so redeemed shall have been made or duly provided for, the holder of any Excess Shares so called for purchase shall cease to be entitled to distributions, voting rights and any and all other benefits with respect to such Shares, except the right to payment of the purchase price for the Shares.

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        The Declaration also requires that Business Combinations between the Company and a beneficial holder of 10% or more of the outstanding Shares (a "Related Person") be approved by the affirmative vote of the holders of at least 75% of the Shares unless (1) the Trustees by unanimous vote or written consent shall have expressly approved in advance the acquisition of the outstanding Shares that caused the Related Person to become a Related Person or shall have approved the Business Combination prior to the Related Person involved in the Business Combination having become a Related Person; or (2) the Business Combination is solely between the Company and a 100% owned affiliate of the Company. As permitted by law, the Company has elected to be governed by such provisions rather than the provisions of Subtitle 6 of Title 3 of the Corporations and Associations Article of the Annotated Code of Maryland regarding business combinations.

        Under the Declaration the number of trustees may be fixed from time to time by two-thirds of the Trustees or by an amendment of the Declaration by the shareholders of the Company, with a minimum of three and a maximum of 12 trustees, a majority of whom must be Independent Trustees. The Declaration fixes the current number of trustees of the Company at five and divides the Trustees into three groups. Trustees in each group are elected to three-year terms. As the Trustees' terms expire, replacements are elected by a majority of the outstanding Shares. The classified nature of the Trustees may make it more difficult for the shareholders to remove the management of the Company than if all trustees were elected on an annual basis. Vacancies may be filled by a majority of the remaining trustees, except that a vacancy among the Independent Trustees must be filled by a majority of the remaining Independent Trustees or by majority vote of the Company's shareholders. Any trustee may be removed for cause by all the remaining trustees, or without cause by vote of two-thirds of the Shares then outstanding and entitled to vote thereon.

        The provisions regarding business combinations and the classified nature of the Trustees and certain other matters may not be repealed or amended without the affirmative vote of at least 75% of the shareholders of the Company, provided that the Trustees, by two-thirds vote, may, without the approval or consent of the shareholders, adopt any amendment that they in good faith determine to be necessary to permit the Company to qualify as a REIT under the Code.

        The foregoing provisions may have the effect of discouraging unilateral tender offers or other takeover proposals which certain shareholders might deem in their interests or pursuant to which they might receive a substantial premium for their Shares. The provisions could also have the effect of insulating current management against the possibility of removal and could, by possibly reducing temporary fluctuations in market price caused by accumulations of Shares, deprive shareholders of opportunities to sell at a temporarily higher market price. However, the Trustees believe that inclusion of the business combination provisions in the Declaration may help assure fair treatment of shareholders and preserve the assets of the Company.

Control Share Acquisition

        Maryland law provides for a limitation of voting rights in a "control share acquisition." The Maryland statute defines a control share acquisition at the 20%, 331/3% and 50% acquisition levels, and requires a two-thirds vote (excluding shares owned by the acquiring person and certain members of management) to accord voting rights to shares acquired in a control share acquisition. The statute would require the target company to hold a special meeting at the request of an actual or proposed control share acquiror subject to compliance with certain conditions by such acquiror. In addition, unless the charter, declaration of trust or by-laws provide otherwise, the statute gives the company, within certain time limitations, various redemption rights if there is a shareholder vote on the issue and the grant of voting rights is not approved, or if an "acquiring person statement" is not delivered to the target company within 10 days following a control share acquisition. Moreover, unless the charter, declaration of trust or by-laws provide otherwise, the statute provides that if, before a control share acquisition occurs, voting rights for control shares are approved at a shareholders' meeting and the acquiror becomes entitled to vote a majority of the shares entitled to vote, then all other shareholders may exercise appraisal rights. The statute does not apply to shares acquired in a merger, consolidation or share exchange if the company is a party to the transaction. An acquisition of shares may be exempted from the control share statute provided that a charter, declaration of trust or by-law provision is adopted for such purpose prior to the control share acquisition. There are no such provisions in the Declaration or By-Laws of the Company.

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Rights Plan

        In October 1994 the Trustees adopted a shareholder rights plan (the "Rights Plan"). The Rights Plans provides for the distribution of one Junior Participating Preferred Share purchase right (a "Right") for each Common Share. Each Right entitles the holder to buy 1/100th of a Junior Participating Preferred Share (or, in certain circumstances, to receive cash, property, Common Shares or other securities of the Company) at an exercise price of $50 per 1/100th of a Junior Participating Preferred Share. Certain powers, preferences and rights and certain qualifications, limitations and restrictions of the Junior Participating Preferred Shares are summarized above under "Description of Preferred Shares—Junior Participating Shares."

        Initially, the Rights are attached to certificates representing Common Shares. The Rights will separate from such Common Shares and a "Distribution Date" will occur upon earlier of (i) 10 business days (or such later date as the Trustees may determine before a Distribution Date occurs) following a public announcement by the Company that a person or group affiliated or associated persons, with certain exceptions (an "Acquiring Person"), has acquired, or has obtained the right to acquire, beneficial ownership of 10% or more of the outstanding Common Shares (the date of such announcement being a "Share Acquisition Date") or (ii) 10 business days (or such later date as the Trustees may determine before a Distribution Date occurs) following the commencement of a tender offer or exchange offer that would result in a person becoming an Acquiring Person.

        Until the Distribution Date, (i) the Rights will be evidenced by the certificates for Common Shares and will be transferred with and only with such Common Share certificates, (ii) Common Share certificates will contain a notation incorporating the rights agreement pursuant to which the Rights were issued (the "Rights Agreement") by reference and (iii) the surrender for transfer of any certificates for Common Shares outstanding will also constitute the transfer of the Rights associated with the Common Shares represented by such certificates.

        The Rights are not exercisable until the Distribution Date and will expire at the close of business on October 17, 2004, unless earlier redeemed or exchanged by the Company as described below. Until a Right is exercised, the holder thereof, as such, has no rights as a shareholder of the Company, including, without limitation, the right to vote or to receive dividends.

        In the event (a "Flip-In Event") a Person becomes an Acquiring Person (except pursuant to a tender or exchange offer for all outstanding Common Shares at a price and on terms which a majority of the Company's Outside Trustees (as defined in the Rights Agreement) determines to be fair to and otherwise in the best interests of the Company and its shareholders (a "fair offer")), each holder of a Right will thereafter have the right to receive, upon exercise of such Right, Common Shares (or, in certain circumstances, cash, property or other securities of the Company) having a Current Market Price (as defined in the Rights Agreement) equal to two times the exercise price of the Right. Notwithstanding the foregoing, following the occurrence of any Flip- In Event, all Rights that are, or (under certain circumstances specified in the Rights Agreement) were, beneficially owned by any Acquiring Person (or by certain related parties) will be null and void in the circumstances set forth in the Rights Agreement. However, Rights will not be exercisable following the occurrence of any Flip-In Event until such time as the Rights are no longer redeemable by the Company as set forth below.

        In the event (a "Flip-Over Event") that, at any time on or after the Share Acquisition Date, (i) the Company shall take part in a merger or other business combination transaction (other than certain mergers that follow a fair offer) and the Company shall not be the surviving entity or (ii) the Company shall take part in a merger or other business combination transaction in which the Common Shares are changed or exchanged (other than certain mergers that follow a fair offer) or (iii) 50% or more of the Company's assets or earning power is sold or transferred, each holder of a Right (except Rights which previously have been voided, as set forth above) shall thereafter have the right to receive, upon exercise, a number of shares of common stock of the acquiring company having a Current Market Price equal to two times the exercise price of the Right. Flip-In Events and Flip-Over Events are collectively referred to as "Triggering Events."

        The Purchase Price payable and the number of Junior Participating Preferred Shares (or the amount of cash, property or other securities) issuable upon exercise of the Rights are subject to adjustment from time to time to prevent dilution (i) in the event of a share dividend on, or a subdivision, combination or reclassification of, the Junior Participating Preferred Shares, (ii) if holders of the Junior Participating Preferred Shares are granted certain rights or warrants to subscribe for Junior Participating Preferred Shares or convertible securities at less than the

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Current Market Price of the Junior Participating Preferred Shares or (iii) upon the distribution to holders of the Junior Participating Preferred Shares of evidences of indebtedness or assets (excluding regular quarterly cash dividends) or of subscription rights or warrants (other than those referred to above). With certain exceptions, no adjustment in the Purchase Price will be required until cumulative adjustments amount to at least 1% of the Purchase Price. The Company is not required to issue fractional Shares upon the exercise of any Right, and in lieu thereof, a cash payment will be made.

        At any time until 10 business days following the Share Acquisition Date, the Company may redeem the Rights in whole, but not in part, at a price of $.01 per Right, payable, at the option of the Company, in cash, Common Shares or other consideration as the Trustees may determine. Immediately upon the effectiveness of the action of the Trustees ordering redemption of the Rights, the Rights will terminate and the only right of the holders of Rights will be to receive the $.01 per Right redemption price.

        The term of the Rights, other than key financial terms and the date on which the Rights expire, may be amended by the Trustees prior to the Distribution Date. Thereafter, the provisions of the Rights Agreement may be amended by the Trustees only in order to cure any ambiguity, defect or inconsistency, to make changes which do not adversely affect the interests of holders of Rights (excluding the interests of any Acquiring Person and certain other related parties) or to shorten or lengthen any time period under the Rights Agreement; provided, however, that no amendment to lengthen the time period governing redemption is permitted to be made at such time as the Rights are not redeemable.


PLAN OF DISTRIBUTION

        The Company may sell the Offered Securities to one or more underwriters for public offering and sale by them or may sell the Offered Securities to investors directly or through agents. Any such underwriter or agent involved in the offer and sale of the Offered Securities will be named in the applicable Prospectus Supplement.

        The distribution of Offered Securities may be effected from time to time in one or more transactions at a fixed price or prices, which may be changed, at market prices prevailing at the time of sale, at prices related to such market prices or at negotiated prices. In connection with the sale of Offered Securities, underwriters or agents may receive or be deemed to have received compensation from the Company or from purchasers in the form of underwriting discounts, concessions or commissions. Underwriters may sell Offered Securities to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters or from purchasers.

        Any underwriting compensation paid by the Company to underwriters or agents in connection with the offering of Offered Securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers, will be set forth in the applicable Prospectus Supplement. Underwriters, dealers and agents participating in the distribution of the Offered Securities may be deemed to be underwriters, and any discounts, concessions and commissions received by them and any profit realized by them on resale of the Offered Securities may be deemed to be underwriting discounts and commissions, under the Securities Act. Underwriters, dealers and agents may be entitled, under agreements entered into with the Company, to indemnification against and contribution toward certain civil liabilities, including liabilities under the Securities Act.

        If so indicated in the applicable Prospectus Supplement, the Company will authorize underwriters or other persons acting as the Company's agents to solicit offers by certain institutions to purchase Offered Securities from the Company at the public offering price set forth in such Prospectus Supplement pursuant to contracts providing for payment and delivery on a future date or dates. Institutions with whom such contracts, when authorized, may be made include commercial and savings banks, insurance companies, pension funds, investment companies, educational and charitable institutions, and other institutions, but will in all cases be subject to the approval of the Company. Any such contracts will be subject to the condition that the purchase by an institution of the Offered Securities covered by its contracts shall not at the time of delivery be prohibited under the law of any jurisdiction in the United States to which such institution is subject and, if a portion of the Offered Securities is being sold to underwriters, may be subject to the condition that the Company shall have sold to such underwriters the Offered Securities not sold for delayed delivery. The underwriters and such other persons will not have any responsibility in respect of the validity or performance of such contracts.

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        Unless otherwise specified in the related Prospectus Supplement, each series of Offered Securities will be a new issue with no established trading market, other than Common Shares which are listed on the New York Stock Exchange. Any Common Shares sold pursuant to a Prospectus Supplement will be listed on such Exchange. The Company may elect to list any other series of Offered Securities on an exchange, but is not obligated to do so. Any underwriters to whom Offered Securities are sold by the Company for public offering and sale may make a market in such Offered Securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. No assurance can be given as to the liquidity of or the trading markets for any Offered Securities.

        Certain of the underwriters and their affiliates may be customers of, engage in transactions with and perform services for the Company and its subsidiaries in the ordinary course of business.

        The specific terms and manner of sale of the Offered Securities will be set forth or summarized in the applicable Prospectus Supplement.


LEGAL MATTERS

        Certain legal matters with respect to the Offered Securities offered by the Company will be passed upon for the Company by Sullivan & Worcester LLP, Boston, Massachusetts. Sullivan & Worcester LLP, will rely, as to all matters of Maryland law, upon one or more opinions of Piper & Marbury L.L.P., Baltimore, Maryland. Barry M. Portnoy, was a partner in the firm of Sullivan & Worcester LLP until March 31, 1997 and is a Managing Trustee of the Company and HPT, a director and 50% shareholder of REIT Management & Research, Inc, the Company's investment advisor ("RMR") and its affiliate, HRPT Advisors, Inc., the predecessor investment advisor of the Company. Mr. Portnoy is also a director and/or significant shareholder of certain lessees of and borrowers from the Company. Sullivan & Worcester LLP represents HPT, RMR, certain of such lessees and borrowers and certain affiliates of each of the foregoing on various matters.


EXPERTS

        The consolidated financial statements and financial statement schedules of the Company included or incorporated by reference in the Company's Annual Report on Form 10-K for the year ended December 31, 1997, have been audited by Ernst & Young LLP, independent auditors, as set forth in their reports thereon included or incorporated by reference therein and incorporated herein by reference which, as to the years 1997 and 1996, are based in part on the report of Arthur Andersen LLP, independent public accountants. Such consolidated financial statements and financial statement schedules are incorporated herein by reference in reliance upon such reports given upon the authority of such firms as experts in accounting and auditing.

        The statement of revenue and certain expenses for 1600 Market Street for the year ended December 31, 1997 included in the Company's Current Report on Form 8-K dated March 30, 1998 has been audited by Ernst & Young LLP, independent auditors, as set forth in their report included therein and incorporated herein by reference. Such financial statements are incorporated herein by reference in reliance upon such report given upon the authority of such firm as experts in accounting and auditing.

        The statement of revenues and certain expenses of 1735 Market Street for the year ended December 31, 1997 incorporated by reference in this Prospectus and elsewhere in the registration statement has been audited by Arthur Andersen LLP, independent public accountants, and is included herein in reliance upon the authority of said firm as experts in giving said reports.

THE AMENDED AND RESTATED DECLARATION OF TRUST OF THE COMPANY, DATED JULY 1, 1994, A COPY OF WHICH, TOGETHER WITH ALL AMENDMENTS THERETO (THE "DECLARATION"), IS DULY FILED IN THE OFFICE OF THE DEPARTMENT OF ASSESSMENTS AND TAXATION OF THE STATE OF MARYLAND, PROVIDES THAT THE NAME "HEALTH AND RETIREMENT PROPERTIES TRUST" REFERS TO THE TRUSTEES UNDER THE DECLARATION COLLECTIVELY AS TRUSTEES, BUT NOT INDIVIDUALLY OR PERSONALLY, AND THAT NO TRUSTEE, OFFICER, SHAREHOLDER, EMPLOYEE OR AGENT OF THE COMPANY SHALL BE HELD TO ANY PERSONAL LIABILITY, JOINTLY OR SEVERALLY, FOR ANY OBLIGATION OF, OR CLAIM AGAINST, THE COMPANY. ALL PERSONS DEALING WITH THE COMPANY, IN ANY WAY, SHALL LOOK ONLY TO THE ASSETS OF THE COMPANY FOR THE PAYMENT OF ANY SUM OR THE PERFORMANCE OF ANY OBLIGATION.

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$250,000,000

HRPT Properties Trust

5.75% Senior Notes due 2014

LOGO

PROSPECTUS SUPPLEMENT

October 23, 2003

Citigroup



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TABLE OF CONTENTS
SUMMARY
RECENT DEVELOPMENTS
USE OF PROCEEDS
RATIO OF EARNINGS TO FIXED CHARGES
DESCRIPTION OF THE NOTES
MATERIAL FEDERAL INCOME TAX CONSIDERATIONS
General
UNDERWRITING
LEGAL MATTERS
EXPERTS
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
WHERE YOU CAN FIND MORE INFORMATION
FORWARD LOOKING STATEMENTS
GLOSSARY
AVAILABLE INFORMATION
INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
THE COMPANY
USE OF PROCEEDS
RATIO OF EARNINGS TO FIXED CHARGES
DESCRIPTION OF DEBT SECURITIES
DESCRIPTION OF SHARES
DESCRIPTION OF PREFERRED SHARES
DESCRIPTION OF DEPOSITARY SHARES
DESCRIPTION OF WARRANTS
DESCRIPTION OF CONVERTIBLE SUBORDINATED DEBENTURES
LIMITATION OF LIABILITY; SHAREHOLDER LIABILITY
REDEMPTION; BUSINESS COMBINATIONS AND CONTROL SHARE ACQUISITIONS
PLAN OF DISTRIBUTION
LEGAL MATTERS
EXPERTS