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Filed Pursuant to Rule 424(b)(5)
Registration No. 333-167982

Subject to Completion
Preliminary Prospectus Supplement dated August 4, 2010

The information in this prospectus supplement and the accompanying prospectus is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not an offer to sell these securities and are not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

PROSPECTUS SUPPLEMENT
(To prospectus dated July 23, 2010)

7,000,000 Shares

Government Properties Income Trust

COMMON SHARES OF BENEFICIAL INTEREST

We are offering 7,000,000 common shares of beneficial interest. Our common shares are listed on the New York Stock Exchange under the symbol "GOV." The last reported sale price on August 3, 2010 was $27.55 per share.

Investing in our common shares involves risks that are described in the "Risk Factors" section of our Annual Report on Form 10-K for the year ended December 31, 2009, or our Annual Report, and our Quarterly Report on Form 10-Q for the quarter ended June 30, 2010.

The underwriters may also purchase from us up to an additional 1,050,000 common shares, at the public offering price, less the underwriting discount, within 30 days from the date of this prospectus supplement to cover overallotments, if any.

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

The common shares will be ready for delivery on or about August      , 2010.

The date of this prospectus supplement is August      , 2010.

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

        This prospectus supplement contains the terms of this offering. A description of our common shares is set forth in the accompanying prospectus under the heading "Description of Shares of Beneficial Interest." This prospectus supplement, or the information incorporated by reference herein, may add, update or change information in the accompanying prospectus (or the information incorporated by reference therein). If information in this prospectus supplement, or the information incorporated by reference herein, is inconsistent with the accompanying prospectus (or the information incorporated by reference therein), this prospectus supplement (or the information incorporated by reference herein) will apply and will supersede that information in the accompanying prospectus (or the information incorporated by reference therein). References to the "prospectus" are to this prospectus supplement, together with the accompanying prospectus, and the information incorporated by reference in each.

        It is important for you to read and consider all information contained in this prospectus supplement, the accompanying prospectus and the information incorporated by reference herein and therein in making your investment decision. You should also read and consider the information in the documents to which we have referred you in "Where You Can Find More Information" in this prospectus supplement and the accompanying prospectus.

        You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not, and the underwriters have not, authorized any person to provide you with different information. If anyone provides you with different or additional information, you should not rely on it. We are not, and the underwriters are not, making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference, is accurate only as of their respective dates. Our business, financial condition, results of operations and prospects may have changed since those dates.

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THE COMPANY

        We are a real estate investment trust, or REIT, which owns and intends to invest in additional properties that are majority leased to government tenants. At June 30, 2010, we owned 41 properties with approximately 4.9 million rentable square feet located in 20 states and the District of Columbia.

Distributions

        Our current cash distribution rate to common shareholders is $0.41 per share per quarter, or $1.64 per share per year. The determination of future distributions will be made by our board of trustees, and will depend upon our earnings, cash available for distribution, financial condition, capital market condition, growth prospects and other factors which our board deems relevant.

        On April 8, 2010, we declared a quarterly distribution of $0.40 per common share for the quarter ended March 31, 2010, which was paid on May 24, 2010 to our shareholders of record as of the close of business on April 23, 2010. On July 1, 2010, we declared a quarterly distribution of $0.41 per common share for the quarter ended June 30, 2010, which we expect will be paid on or about August 16, 2010 to our shareholders of record as of the close of business on July 16, 2010. We expect the next quarterly distribution for the quarter ended September 30, 2010 to be declared in October 2010 and paid in November 2010. Shareholders who purchase shares in this offering will not be entitled to receive the quarterly distribution to be paid in August 2010 but the purchasers that continue to hold their shares through the relevant record date will receive the full amount of any distribution that our board of trustees declares for the quarter ending September 30, 2010.

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) 219-1440.

THE OFFERING

        The number of common shares to be outstanding after the offering is based on 31,263,850 common shares outstanding on August 3, 2010. If the underwriters exercise their overallotment option in full, we will issue an additional 1,050,000 common shares.

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USE OF PROCEEDS

        We estimate that our net proceeds from this offering, after deducting the underwriting discount and other estimated offering expenses, will be $             million. If the underwriters exercise their overallotment option, we estimate that our net proceeds will be approximately $             million. We expect to use the net proceeds from this offering to repay the amounts outstanding under our $250 million revolving credit facility and fund general business activities, including possible future acquisitions. As of July 31, 2010, our $250 million revolving credit facility had an outstanding balance of $132 million and an interest rate of 3.34% per annum. We borrowed amounts under our revolving credit facility to pay for acquisitions, certain operating expenses and for working capital purposes. Our revolving credit facility bears interest at LIBOR plus a spread that varies depending on the amount of our debt leverage and matures on April 24, 2012. Subject to certain conditions, including the payment of a fee, this facility's maturity date may be extended, at our option, to April 24, 2013. Affiliates of Morgan Stanley & Co. Incorporated, RBC Capital Markets Corporation, Wells Fargo Securities, LLC, Citigroup Global Markets Inc., Morgan Keegan & Company, Inc. and UBS Securities LLC are lenders under our revolving credit facility and will receive a pro rata portion of net proceeds from this offering used to repay amounts outstanding thereunder.

        Depending on market conditions at the time of pricing of this offering and other considerations, we may sell fewer or more common shares than the number set forth on the cover page of this prospectus supplement.

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FEDERAL INCOME TAX AND ERISA CONSIDERATIONS

        The following supplements and updates the summary of U.S. federal income tax considerations and Employee Retirement Income Security Act of 1974, as amended, or ERISA, considerations relating to the acquisition, ownership and disposition of our common shares in our Annual Report, which is incorporated in this prospectus supplement by reference. Sullivan & Worcester LLP, Boston, Massachusetts, has rendered a legal opinion that the discussions in this section and in the sections of our Annual Report captioned "Federal Income Tax Considerations" and "ERISA Plans, Keogh Plans and Individual Retirement Accounts" are accurate in all material respects and, taken together, fairly summarize the U.S. federal income tax and ERISA issues discussed in those sections, and the opinions of counsel referred to in those sections represent Sullivan & Worcester LLP's opinions on those subjects. Specifically, subject to qualifications and assumptions contained in its opinion and in our Annual Report, Sullivan & Worcester LLP has given opinions to the effect (1) that we have been organized and will have qualified as a REIT under the Internal Revenue Code of 1986, as amended, or the Tax Code, for our taxable year ending December 31, 2009 upon our filing a timely REIT federal income tax return for that year, and that our current investments and plan of operation will enable us to continue to meet the requirements for qualification and taxation as a REIT under the Tax Code, it being understood that our actual qualification as a REIT, however, will depend on our continued ability to meet, and our meeting, through actual annual operating results and distributions, the various qualification tests under the Tax Code, and (2) that under the "plan assets" regulations promulgated by the U.S. Department of Labor under ERISA, our common shares are "publicly offered securities" and our assets will not be deemed to be "plan assets" under ERISA.

        Subject to the detailed discussion contained in our Annual Report, we believe that, upon our filing a timely REIT federal income tax return for our taxable year ending December 31, 2009, we will have qualified, and we intend to remain qualified, as a REIT under the Tax Code. As a REIT, we generally will not be subject to federal income tax on our net income distributed as dividends to our shareholders. Our distributions to you generally are includable in your income as dividends to the extent these distributions do not exceed allocable current or accumulated earnings and profits; distributions in excess of allocable current or accumulated earnings and profits generally are treated for tax purposes as a return of capital to the extent of your basis in our common shares, and reduce your basis. Subject to the detailed discussion contained in our Annual Report, we intend to conduct our affairs so that our assets are not deemed to be "plan assets" of any individual retirement account, employee benefit plan subject to Title 1 of ERISA, or other qualified retirement plan subject to Section 4975 of the Tax Code which acquires our common shares.

        Information reporting and backup withholding may apply to payments you receive on our common shares, as described in our Annual Report. Backup withholding is not an additional tax. Any amounts so withheld may be allowed as a credit against your U.S. federal income tax liability and, if backup withholding results in an overpayment of taxes, a refund may be obtained from the Internal Revenue Service, or the IRS, provided that you furnish the required information to the IRS. The backup withholding rate is currently 28% and is scheduled to increase to 31% after 2010.

        Effective generally after December 31, 2012, the reporting obligations of non-U.S. financial institutions and other non-U.S. entities is increased for purposes of identifying accounts and investments held directly or indirectly by United States persons, and the failure to comply will trigger a 30% withholding tax on certain dividends and related payments to these non-U.S. persons. In addition, for taxable years beginning after December 31, 2012, U.S. holders who are individuals, estates or certain trusts and whose income exceeds applicable thresholds will generally be required to pay a new, 3.8% Medicare tax, which will apply to dividends and gains such as dividends on our shares and gains from the disposition of our shares.

        We encourage you to consult your tax advisor regarding the specific federal, state, local, foreign and other tax and ERISA consequences to you of the acquisition, ownership and disposition of our common shares.

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UNDERWRITING

        Under the terms and subject to the conditions contained in the underwriting agreement dated the date of this prospectus supplement, the underwriters named below, for whom Morgan Stanley & Co. Incorporated, RBC Capital Markets Corporation and Wells Fargo Securities, LLC are serving as the representatives, have severally agreed to purchase, and we have agreed to sell to the underwriters the number of common shares listed opposite their names below:

        The underwriters have agreed to purchase all of the common shares sold under the underwriting agreement if any of the common shares are purchased. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the nondefaulting underwriters may be increased or the underwriting agreement may be terminated.

        We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended, or to contribute to payments the underwriters may be required to make in respect of those liabilities.

        The underwriters are offering the common shares, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel, including the validity of the common shares, and other conditions contained in the underwriting agreement, such as the receipt by the underwriters of officers' certificates and legal opinions. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Commissions and Discounts

        The representatives have advised us that the underwriters propose initially to offer the common shares to the public at the public offering price on the cover page of this prospectus supplement and to dealers at that price less a concession not in excess of $            per share. After the public offering, the public offering price and concession may be changed.

        The following table shows the public offering price, underwriting discount and proceeds, before expenses, to us. The information assumes either no exercise or full exercise by the underwriters of their overallotment option.

        The expenses of the offering, not including the underwriting discount, are estimated at approximately $                        and are payable by us.

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Overallotment Option

        We have granted an option to the underwriters to purchase up to an additional 1,050,000 common shares at the public offering price less the underwriting discount. The underwriters may exercise this option for 30 days from the date of this prospectus supplement solely to cover overallotments, if any. If the underwriters exercise this option, each will be obligated, subject to conditions contained in the underwriting agreement, to purchase a number of additional common shares proportionate to that underwriter's initial amount reflected in the above table.

No Sales of Similar Securities

        We, our executive officers, our trustees and CommonWealth REIT, or CWH, have agreed, with exceptions, not to offer, sell, contract to sell, grant any option to purchase or otherwise dispose of any of our common shares or any securities convertible into or exercisable or exchangeable for common shares, or warrants to purchase common shares, and not to take certain other actions relating to our common shares, for a period of 60 days after the date of this prospectus supplement without the prior written consent of Morgan Stanley & Co. Incorporated.

New York Stock Exchange Listing

        Our common shares are listed on the New York Stock Exchange under the symbol "GOV."

Price Stabilization, Short Positions

        Until the distribution of the common shares is completed, SEC rules may limit the underwriters and selling group members from bidding for and purchasing our common shares. However, the underwriters may engage in transactions that stabilize the price of the common shares, such as bids or purchases to peg, fix or maintain that price.

        If the underwriters create a short position in the common shares in connection with the offering, i.e., if they sell more common shares than are listed on the cover of this prospectus supplement, the underwriters may reduce that short position by purchasing common shares in the open market. The underwriters may also elect to reduce any short position by exercising all or part of the overallotment option described above. Purchases of the common shares to stabilize their price or to reduce a short position may cause the price of the common shares to be higher than it might be in the absence of such purchases.

        Neither we nor any of the underwriters makes any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of the common shares. In addition, neither we nor any of the underwriters makes any representation that the underwriters will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.

Electronic Distribution

        A prospectus supplement and accompanying prospectus in electronic format may be made available on the websites maintained by one or more underwriters. Other than the prospectus supplement and accompanying prospectus in electronic format, the information on the underwriters' websites is not part of this prospectus.

Other Relationships

        Some of the underwriters and their affiliates have engaged in, and may in the future engage in, investment banking and other commercial dealings in the ordinary course of business with us. They have received, and may in the future receive, customary fees and commissions for these transactions. Affiliates of Morgan Stanley & Co. Incorporated, RBC Capital Markets Corporation, Wells Fargo Securities, LLC, Citigroup Global Markets Inc., Morgan Keegan & Company, Inc. and UBS Securities LLC are lenders under our revolving credit facility and will receive a pro rata portion of the net proceeds from this offering used to repay amounts outstanding thereunder.

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LEGAL MATTERS

        Venable LLP, Baltimore, Maryland, our Maryland counsel, will issue an opinion about the legality of the common shares. Sullivan & Worcester LLP, Boston, Massachusetts, our lawyers, and Sidley Austin LLP, New York, New York, the underwriters' lawyers, will each also issue an opinion to the underwriters as to certain matters. Sullivan & Worcester LLP and Sidley Austin LLP will rely, as to certain matters of Maryland law, upon the opinion of Venable LLP. Sullivan & Worcester LLP and Venable LLP represent CWH and certain of its affiliates. Sullivan & Worcester LLP also represents Reit Management & Research LLC, or RMR, which is our manager, and certain of its affiliates on various matters.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

        The SEC allows us to "incorporate by reference" the information we file with it, which means that we can disclose important information to you by referring you to documents previously filed with the SEC. 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 Securities Exchange Act of 1934, as amended, or the Exchange Act:

•

Our Annual Report;



•

Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2010 and June 30, 2010;



•

The information identified as incorporated by reference under Items 10, 11, 12, 13 and 14 of Part III of our Annual Report, from our definitive Proxy Statement for our Annual Meeting of Shareholders filed February 22, 2010;



•

Our Current Reports on Form 8-K dated March 25, 2010, May 13, 2010, June 18, 2010, as amended, July 2, 2010 and July 21, 2010, as amended; and



•

The description of our common shares contained in our registration statement on Form 8-A dated May 20, 2009, and including all amendments and reports filed for the purpose of updating such description.

        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 offering of the common shares:

•

Reports filed under Sections 13(a) and (c) of the Exchange Act;



•

Definitive proxy or information statements filed under Section 14 of the Exchange Act in connection with any subsequent shareholders' meeting; and



•

Any reports filed under Section 15(d) of the Exchange Act.

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

Investor Relations
Government Properties Income Trust
400 Centre Street
Newton, Massachusetts 02458
(617) 219-1410

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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 100 F Street N.E., Room 1580, 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 website at http://www.sec.gov.

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WARNING CONCERNING FORWARD LOOKING STATEMENTS

        THIS PROSPECTUS SUPPLEMENT, THE ACCOMPANYING PROSPECTUS, AND THE DOCUMENTS INCORPORATED BY REFERENCE CONTAIN STATEMENTS WHICH CONSTITUTE FORWARD LOOKING STATEMENTS WITHIN THE MEANING OF THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995 AND OTHER FEDERAL SECURITIES LAWS. WHENEVER WE USE WORDS SUCH AS "BELIEVE", "EXPECT", "ANTICIPATE", "INTEND", "PLAN", "ESTIMATE" OR SIMILAR EXPRESSIONS, WE ARE MAKING FORWARD LOOKING STATEMENTS. THESE FORWARD LOOKING STATEMENTS AND THEIR IMPLICATIONS ARE BASED UPON OUR PRESENT INTENT, BELIEFS OR EXPECTATIONS, BUT FORWARD LOOKING STATEMENTS AND THEIR IMPLICATIONS ARE NOT GUARANTEED TO OCCUR AND MAY NOT OCCUR. FORWARD LOOKING STATEMENTS IN THIS PROSPECTUS SUPPLEMENT, THE ACCOMPANYING PROSPECTUS, AND THE DOCUMENTS INCORPORATED BY REFERENCE RELATE TO VARIOUS ASPECTS OF OUR BUSINESS, INCLUDING:

•

OUR ABILITY TO PAY DISTRIBUTIONS IN THE FUTURE AND THE EXPECTED AMOUNTS THEREOF,



•

OUR ACQUISITION AND SALE OF PROPERTIES,



•

THE CREDIT QUALITY OF OUR TENANTS,



•

THE LIKELIHOOD THAT OUR TENANTS WILL PAY RENT, RENEW LEASES, SIGN NEW LEASES OR BE AFFECTED BY CYCLICAL ECONOMIC CONDITIONS,



•

OUR ABILITY TO PAY INTEREST ON AND PRINCIPAL OF OUR DEBT,



•

OUR POLICIES AND PLANS REGARDING INVESTMENTS AND FINANCINGS,



•

THE FUTURE AVAILABILITY OF BORROWINGS UNDER OUR REVOLVING CREDIT FACILITY,



•

OUR ABILITY TO COMPETE FOR ACQUISITIONS AND TENANCIES EFFECTIVELY,



•

OUR TAX STATUS AS A REIT,



•

OUR ABILITY TO RAISE EQUITY OR DEBT CAPITAL,



•

OUR EXPECTATION THAT WE WILL BENEFIT FINANCIALLY BY PARTICIPATING IN AFFILIATES INSURANCE COMPANY, OR AIC, WITH RMR AND OTHER COMPANIES TO WHICH RMR PROVIDES MANAGEMENT SERVICES, AND



•

OTHER MATTERS.

        OUR ACTUAL RESULTS MAY DIFFER MATERIALLY FROM THOSE CONTAINED IN OR IMPLIED BY OUR FORWARD LOOKING STATEMENTS AS A RESULT OF VARIOUS FACTORS. FACTORS THAT COULD HAVE A MATERIAL ADVERSE EFFECT ON OUR FORWARD LOOKING STATEMENTS AND UPON OUR BUSINESS, RESULTS OF OPERATIONS, FINANCIAL CONDITION, FUNDS FROM OPERATIONS, CASH AVAILABLE FOR DISTRIBUTION, CASH FLOWS, LIQUIDITY AND PROSPECTS INCLUDE, BUT ARE NOT LIMITED TO:

•

THE IMPACT OF CHANGES IN THE ECONOMY AND THE CAPITAL MARKETS,



•

COMPETITION WITHIN THE REAL ESTATE INDUSTRY,



•

ACTUAL AND POTENTIAL CONFLICTS OF INTEREST WITH OUR MANAGING TRUSTEES, CWH AND RMR AND THEIR AFFILIATES,



•

COMPLIANCE WITH, AND CHANGES TO, FEDERAL, STATE AND LOCAL LAWS AND REGULATIONS, ACCOUNTING RULES, TAX LAWS AND SIMILAR MATTERS, AND

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LIMITATIONS IMPOSED ON OUR BUSINESS AND OUR ABILITY TO SATISFY COMPLEX RULES IN ORDER FOR US TO QUALIFY AS A REIT FOR U.S. FEDERAL INCOME TAX PURPOSES.

FOR EXAMPLE:

•

IF THE AVAILABILITY OF DEBT CAPITAL REMAINS RESTRICTED OR BECOMES MORE RESTRICTED, WE MAY BE UNABLE TO REFINANCE OR REPAY OUR DEBT OBLIGATIONS WHEN THEY BECOME DUE OR ON TERMS WHICH ARE AS FAVORABLE AS WE NOW HAVE,



•

CONTINGENCIES IN OUR ACQUISITIONS MAY CAUSE THESE TRANSACTIONS NOT TO OCCUR OR TO BE DELAYED,



•

OUR ABILITY TO MAKE FUTURE DISTRIBUTIONS DEPENDS UPON A NUMBER OF FACTORS INCLUDING OUR FUTURE EARNINGS. WE MAY BE UNABLE TO MAINTAIN OUR CURRENT RATE OF DISTRIBUTIONS AND FUTURE DISTRIBUTIONS MAY BE SUSPENDED OR PAID AT A LESSER RATE THAN THE DISTRIBUTIONS WE NOW PAY,



•

OUR ABILITY TO GROW OUR BUSINESS AND INCREASE OUR DISTRIBUTIONS DEPENDS IN LARGE PART UPON OUR ABILITY TO BUY PROPERTIES AND LEASE THEM FOR RENTS WHICH EXCEED OUR CAPITAL COSTS. WE MAY BE UNABLE TO IDENTIFY PROPERTIES THAT WE WANT TO ACQUIRE OR TO NEGOTIATE ACCEPTABLE PURCHASE PRICES, ACQUISITION FINANCING OR LEASE TERMS FOR NEW PROPERTIES,



•

SOME OF OUR TENANTS MAY NOT RENEW EXPIRING LEASES, AND WE MAY BE UNABLE TO LOCATE NEW TENANTS TO MAINTAIN THE HISTORICAL OCCUPANCY RATES OF, OR RENTS FROM, OUR PROPERTIES,



•

RENTS THAT WE CAN CHARGE AT OUR PROPERTIES MAY DECLINE, AND



•

OUR PARTICIPATION IN AIC INVOLVES POTENTIAL FINANCIAL RISKS AND REWARDS TYPICAL OF ANY START UP BUSINESS VENTURE AS WELL AS OTHER FINANCIAL RISKS AND REWARDS SPECIFIC TO INSURANCE COMPANIES. ACCORDINGLY, OUR EXPECTED FINANCIAL BENEFITS FROM OUR INITIAL OR FUTURE INVESTMENTS IN AIC MAY BE DELAYED OR MAY NOT OCCUR.

        THESE RESULTS COULD OCCUR DUE TO MANY DIFFERENT CIRCUMSTANCES, SOME OF WHICH ARE BEYOND OUR CONTROL, SUCH AS GOVERNMENT TENANTS' NEEDS FOR LEASED SPACE, OR CHANGES IN THE CAPITAL MARKETS OR THE ECONOMY GENERALLY.

        THE INFORMATION CONTAINED IN OUR ANNUAL REPORT AND SUBSEQUENT DOCUMENTS FILED WITH THE SEC AND INCORPORATED HEREIN BY REFERENCE IDENTIFIES OTHER FACTORS THAT COULD CAUSE DIFFERENCES FROM OUR FORWARD LOOKING STATEMENTS. ALSO, OTHER FACTORS THAT COULD CAUSE OUR ACTUAL RESULTS TO DIFFER MATERIALLY FROM THOSE IN OUR FORWARD LOOKING STATEMENTS ARE DESCRIBED MORE FULLY UNDER "RISK FACTORS" IN OUR ANNUAL REPORT AND IN OUR QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTER ENDED JUNE 30, 2010.

        YOU SHOULD NOT PLACE UNDUE RELIANCE UPON OUR FORWARD LOOKING STATEMENTS.

        EXCEPT AS REQUIRED BY LAW, WE DO NOT INTEND TO UPDATE OR CHANGE ANY FORWARD LOOKING STATEMENTS AS A RESULT OF NEW INFORMATION, FUTURE EVENTS OR OTHERWISE.

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STATEMENT CONCERNING LIMITED LIABILITY

        THE AMENDED AND RESTATED DECLARATION OF TRUST ESTABLISHING GOVERNMENT PROPERTIES INCOME TRUST, DATED JUNE 8, 2009, AS AMENDED, AS FILED WITH THE STATE DEPARTMENT OF ASSESSMENTS AND TAXATION OF MARYLAND, PROVIDES THAT NO TRUSTEE, OFFICER, SHAREHOLDER, EMPLOYEE OR AGENT OF GOVERNMENT PROPERTIES INCOME TRUST SHALL BE HELD TO ANY PERSONAL LIABILITY, JOINTLY OR SEVERALLY, FOR ANY OBLIGATION OF, OR CLAIM AGAINST, GOVERNMENT PROPERTIES INCOME TRUST. ALL PERSONS DEALING WITH GOVERNMENT PROPERTIES INCOME TRUST IN ANY WAY SHALL LOOK ONLY TO THE ASSETS OF GOVERNMENT PROPERTIES INCOME TRUST FOR THE PAYMENT OF ANY SUM OR THE PERFORMANCE OF ANY OBLIGATION.

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PROSPECTUS

$1,000,000,000

Government Properties Income Trust

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

        We may offer and sell, from time to time, in one or more offerings:

•

debt securities;



•

common shares of beneficial interest;



•

preferred shares of beneficial interest;



•

depositary shares; and



•

warrants.

These securities may be offered and sold separately or together in units with other securities described in this prospectus. Our debt securities may be senior or subordinated.

        The securities described in this prospectus offered by us may be issued in one or more series or issuances. The total offering price will not exceed $1,000,000,000. We may offer and sell these securities to or through one or more underwriters, dealers and agents or directly to purchasers, on a continuous or delayed basis. We will provide the specific terms of any securities actually offered and the manner in which the securities will be offered in supplements to this prospectus. You should carefully read this prospectus and the supplements before you decide to invest in any of these securities.

        The applicable prospectus supplement will also contain information, where applicable, about United States federal income tax considerations and any listing on a securities exchange. Our common shares are listed on the New York Stock Exchange, or the NYSE, under the symbol "GOV."

        Investment in any securities offered by this prospectus involves risk. See "Risk Factors" on page 1 of this prospectus, in our periodic reports filed from time to time with the Securities and Exchange Commission and in the applicable prospectus supplement.

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

The date of this prospectus is July 23, 2010.

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ABOUT THIS PROSPECTUS

        This prospectus is part of a registration statement we filed with the Securities and Exchange Commission, or the SEC, using a "shelf" registration process. Under this shelf process, we may sell any combination of the securities described in this prospectus from time to time in one or more offerings up to a total amount of proceeds of $1,000,000,000.

        This prospectus provides you only with a general description of the securities we may offer. Each time we sell securities, a prospectus supplement will be provided containing specific information about the terms of that offering. The prospectus supplement may also add to, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under the headings "Where You Can Find More Information" and "Documents Incorporated By Reference."

        You should rely only on the information incorporated by reference or provided in this prospectus or any relevant prospectus supplement. We have not authorized anyone to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We will not make an offer of these securities in any jurisdiction where it is unlawful. You should assume that the information in this prospectus, as well as the information we have previously filed with the SEC and incorporated by reference in this prospectus, is accurate only as of the date of the documents containing the information.

        References in this prospectus to "we", "us", "our" or "GOV" mean Government Properties Income Trust. References in this prospectus to our "declaration of trust" and our "bylaws" refer to our Amended and Restated Declaration of Trust, as amended, and our Amended and Restated Bylaws, respectively.

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WARNING CONCERNING FORWARD LOOKING STATEMENTS

        THIS PROSPECTUS, INCLUDING THE DOCUMENTS THAT ARE INCORPORATED BY REFERENCE, CONTAINS STATEMENTS AND IMPLICATIONS WHICH CONSTITUTE FORWARD LOOKING STATEMENTS WITHIN THE MEANING OF THE PRIVATE SECURITIES LITIGATION REFORM ACT OF 1995 AND OTHER FEDERAL SECURITIES LAWS. WHENEVER WE USE WORDS SUCH AS "BELIEVE", "EXPECT", "ANTICIPATE", "INTEND", "PLAN", "ESTIMATE" OR SIMILAR EXPRESSIONS, WE ARE MAKING FORWARD LOOKING STATEMENTS. THESE FORWARD LOOKING STATEMENTS ARE BASED UPON OUR PRESENT INTENT, BELIEFS OR EXPECTATIONS, BUT FORWARD LOOKING STATEMENTS ARE NOT GUARANTEED TO OCCUR AND MAY NOT OCCUR. FORWARD LOOKING STATEMENTS RELATE TO VARIOUS ASPECTS OF OUR BUSINESS, INCLUDING:

•

OUR ABILITY TO PAY DISTRIBUTIONS IN THE FUTURE AND THE EXPECTED AMOUNTS THEREOF,



•

OUR ABILITY TO PAY INTEREST ON AND PRINCIPAL OF OUR DEBT,  



•

OUR POLICIES AND PLANS REGARDING INVESTMENTS AND FINANCINGS,  



•

THE FUTURE AVAILABILITY OF BORROWINGS UNDER OUR REVOLVING CREDIT FACILITY,  



•

OUR TAX STATUS AS A REAL ESTATE INVESTMENT TRUST, OR REIT,  



•

OUR ABILITY TO RAISE EQUITY OR DEBT CAPITAL, AND  



•

OTHER MATTERS.  

        OUR ACTUAL RESULTS MAY DIFFER MATERIALLY FROM THOSE CONTAINED IN OR IMPLIED BY OUR FORWARD LOOKING STATEMENTS AS A RESULT OF VARIOUS FACTORS. FACTORS THAT COULD HAVE A MATERIAL ADVERSE EFFECT ON OUR FORWARD LOOKING STATEMENTS AND UPON OUR BUSINESS, RESULTS OF OPERATIONS, FINANCIAL CONDITION, FUNDS FROM OPERATIONS, CASH AVAILABLE FOR DISTRIBUTION, CASH FLOWS, LIQUIDITY AND PROSPECTS INCLUDE, BUT ARE NOT LIMITED TO:

•

THE IMPACT OF CHANGES IN THE ECONOMY AND THE CAPITAL MARKETS,  



•

COMPETITION WITHIN THE REAL ESTATE INDUSTRY,  



•

ACTUAL AND POTENTIAL CONFLICTS OF INTEREST WITH OUR MANAGING TRUSTEES AND OUR MANAGER, REIT MANAGEMENT & RESEARCH LLC, AND THEIR AFFILIATES,



•

COMPLIANCE WITH, AND CHANGES TO, FEDERAL, STATE AND LOCAL LAWS AND REGULATIONS, ACCOUNTING RULES, TAX LAWS AND SIMILAR MATTERS, AND  



•

LIMITATIONS IMPOSED ON OUR BUSINESS AND OUR ABILITY TO SATISFY COMPLEX RULES IN ORDER FOR US TO QUALIFY AS A REIT FOR U.S. FEDERAL INCOME TAX PURPOSES.

FOR EXAMPLE:

•

IF THE AVAILABILITY OF DEBT CAPITAL REMAINS RESTRICTED OR BECOMES MORE RESTRICTED, WE MAY BE UNABLE TO REFINANCE OR REPAY OUR DEBT OBLIGATIONS WHEN THEY BECOME DUE OR ON TERMS WHICH ARE AS FAVORABLE AS WE NOW HAVE,

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•

OUR ABILITY TO MAKE FUTURE DISTRIBUTIONS DEPENDS UPON A NUMBER OF FACTORS INCLUDING OUR FUTURE EARNINGS. WE MAY BE UNABLE TO MAINTAIN OUR CURRENT RATE OF DISTRIBUTIONS AND FUTURE DISTRIBUTIONS MAY BE SUSPENDED OR PAID AT A LESSER RATE THAN THE DISTRIBUTIONS WE NOW PAY, AND



•

OUR ABILITY TO GROW OUR BUSINESS AND INCREASE OUR DISTRIBUTIONS DEPENDS IN LARGE PART UPON OUR ABILITY TO BUY PROPERTIES AND LEASE THEM FOR RENTS WHICH EXCEED OUR CAPITAL COSTS. WE MAY BE UNABLE TO IDENTIFY PROPERTIES THAT WE WANT TO ACQUIRE OR TO NEGOTIATE ACCEPTABLE PURCHASE PRICES, ACQUISITION FINANCING OR LEASE TERMS FOR NEW PROPERTIES.

        THESE RESULTS COULD OCCUR DUE TO MANY DIFFERENT CIRCUMSTANCES, SOME OF WHICH ARE BEYOND OUR CONTROL, SUCH AS GOVERNMENT TENANTS' NEEDS FOR LEASED SPACE, OR CHANGES IN THE CAPITAL MARKETS OR THE ECONOMY GENERALLY.

        OTHER IMPORTANT FACTORS THAT COULD CAUSE ACTUAL RESULTS TO DIFFER MATERIALLY FROM THOSE IN OUR FORWARD LOOKING STATEMENTS ARE DESCRIBED MORE FULLY IN OUR MOST RECENTLY FILED ANNUAL REPORT ON FORM 10-K AND OUR SUBSEQUENTLY FILED QUARTERLY REPORTS ON FORM 10-Q, INCLUDING THOSE DESCRIBED UNDER THE CAPTION "ITEM 1A. RISK FACTORS," AND OTHER REPORTS FILED FROM TIME TO TIME WITH THE SEC AND ANY PROSPECTUS SUPPLEMENT.

        THE INFORMATION CONTAINED ELSEWHERE IN THIS PROSPECTUS OR INCORPORATED HEREIN IDENTIFIES OTHER IMPORTANT FACTORS THAT COULD CAUSE DIFFERENCES FROM OUR FORWARD LOOKING STATEMENTS.

        YOU SHOULD NOT PLACE UNDUE RELIANCE UPON OUR FORWARD LOOKING STATEMENTS.

        EXCEPT AS REQUIRED BY LAW, WE DO NOT INTEND TO UPDATE OR CHANGE ANY FORWARD LOOKING STATEMENTS AS A RESULT OF NEW INFORMATION, FUTURE EVENTS OR OTHERWISE.

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GOVERNMENT PROPERTIES INCOME TRUST

        We are organized as a Maryland real estate investment trust, or REIT, that owns and intends to invest in properties that are majority leased to government tenants. As of March 31, 2010, we owned 35 properties, located in 16 states and the District of Columbia, containing approximately 4.4 million rentable square feet, of which 96.8% is leased to the U.S. Government and four state governments. We intend to elect and qualify to be taxed as a REIT for U.S. federal income tax purposes, commencing with our taxable year ended December 31, 2009.

        Our principal place of business is 400 Centre Street, Newton, Massachusetts 02458, and our telephone number is (617) 219-1440.

RISK FACTORS

        Investment in any securities offered pursuant to this prospectus involves risks. You should carefully consider the risk factors incorporated by reference to our most recent Annual Report on Form 10-K and our subsequent Quarterly Reports on Form 10-Q and the other information contained in this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement before acquiring any of such securities.

USE OF PROCEEDS

        Unless otherwise described in a prospectus supplement, we intend to use the net proceeds from the sale of any securities under this prospectus for general business purposes, which may include acquiring and investing in additional properties and the repayment of borrowings under our revolving credit facility or other debt. Until the proceeds from a sale of securities by us are applied to their intended purposes, they will be invested in short-term investments, including repurchase agreements, some or all of which may not be investment grade.

RATIO OF EARNINGS TO FIXED CHARGES

        The following table sets forth our ratio of earnings to fixed charges for the periods indicated:

        The ratio of earnings to fixed charges presented above was computed using our consolidated earnings and our consolidated fixed charges. For these purposes, earnings have been calculated by adding fixed charges to net income. Fixed charges consist of interest costs, whether expensed or capitalized, and any interest component of capitalized lease expense, and amortization of debt discounts and deferred financing costs, whether expensed or capitalized. We did not capitalize any interest costs or incur any capitalized lease expense during any of the periods presented above. Ratios of earnings to fixed charges and preferred dividends are not presented because there was no outstanding preferred stock in any of the periods indicated.

        We were formed as a 100% owned subsidiary of CommonWealth REIT, or CWH, and commenced operations on February 17, 2009. We remained a wholly owned subsidiary of CWH until we closed our initial public offering on June 8, 2009 and we became a separately traded public company. For periods prior to our initial public offering and prior to our formation, our financial information was consolidated with CWH. Because of this, our historical results of operations for periods prior to June 8, 2009 and the related ratios do not necessarily reflect what our results of operations, financial

1

position and cash flows would have been if we had operated as a stand-alone company, are not comparable to our results or ratios since then and should not be relied upon as an indicator of our future performance. For more information about our historical financial statements, please refer to our filings with the SEC, including our Annual Report on Form 10-K for the fiscal year ended December 31, 2009 (including the section captioned "Risk Factors—Our audited financial statements may not be representative of our results as an independent public company").

DESCRIPTION OF DEBT SECURITIES

        The following is a summary of the material terms of the debt securities we may offer under this prospectus. Because it is a summary, it does not contain all of the information that may be important to you. If you want more information, you should read the forms of indentures which we have filed as exhibits to the registration statement of which this prospectus is a part. We will file any final indentures and supplemental indentures if we issue debt securities. See "Where You Can Find More Information." This summary is also subject to and qualified by reference to the descriptions of the particular terms of your securities described in the applicable prospectus supplement.

        The debt securities sold under this prospectus will be our direct obligations, which may be secured or unsecured, and which may be senior or subordinated indebtedness. Our debt securities will be issued under one or more indentures between us and a trustee. Any indenture will be subject to and governed by the Trust Indenture Act. The statements made in this prospectus relating to any indentures and the debt securities to be issued under the indentures are summaries of certain anticipated provisions of the indentures and are not complete.

General

        We may issue debt securities that rank "senior," "senior subordinated" or "junior subordinated." The debt securities that we refer to as "senior" will be our direct obligations and will rank equally and ratably in right of payment with our other indebtedness not subordinated. We may issue debt securities that will be subordinated in right of payment to the prior payment in full of senior debt, as defined in the applicable prospectus supplement, and may rank equally and ratably with the other senior subordinated indebtedness. We refer to these as "senior subordinated" securities. We may also issue debt securities that may be subordinated in right of payment to the senior subordinated securities. These would be "junior subordinated" securities. We have filed with the registration statement of which this prospectus is a part, three separate forms of indenture, one for the senior securities, one for the senior subordinated securities and one for the junior subordinated securities. We refer to senior subordinated and junior subordinated securities as "subordinated."

        We may issue the debt securities without limit as to aggregate principal amount, in one or more series, in each case as we establish in one or more supplemental indentures. We need not issue all debt securities of one series at the same time. Unless we otherwise provide, we may reopen a series, without the consent of the holders of the series, for issuances of additional securities of that series.

        We anticipate that any indenture will provide that we may, but need not, designate more than one trustee under an indenture, each with respect to one or more series of debt securities. Any trustee under any indenture may resign or be removed with respect to one or more series of debt securities, and we may appoint a successor trustee to act with respect to that series.

        The applicable prospectus supplement will describe the specific terms relating to the series of debt securities we will offer, including, where applicable, the following:

•

the title and series designation and whether they are senior securities, senior subordinated securities or junior subordinated securities;



•

the aggregate principal amount of the securities;

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•

the percentage of the principal amount at which we will issue the debt securities and, if other than the principal amount of the debt securities, the portion of the principal amount of the debt securities payable upon maturity of the debt securities;



•

if convertible, the initial conversion price, the conversion period and any other terms governing such conversion;



•

the stated maturity date;



•

any fixed or variable interest rate or rates per annum;



•

the place where principal, premium, if any, and interest will be payable and where the debt securities can be surrendered for transfer, exchange or conversion;



•

the date from which interest may accrue and any interest payment dates;



•

any sinking fund requirements;



•

any provisions for redemption, including the redemption price and any remarketing arrangements;



•

whether the securities are denominated or payable in United States dollars or a foreign currency or units of two or more foreign currencies;



•

whether the amount of payments of principal or premium, if any, or interest on the debt securities may be determined with reference to an index, formula or other method and the manner in which such amounts shall be determined;



•

the events of default and covenants of such securities, to the extent different from or in addition to those described in this prospectus;



•

whether we will issue the debt securities in certificated or book-entry form;



•

whether the debt securities will be in registered or bearer form and, if in registered form, the denominations if other than in even multiples of $1,000 and, if in bearer form, the denominations and terms and conditions relating thereto;



•

whether we will issue any of the debt securities in permanent global form and, if so, the terms and conditions, if any, upon which interests in the global security may be exchanged, in whole or in part, for the individual debt securities represented by the global security;



•

the applicability, if any, of the defeasance and covenant defeasance provisions described in this prospectus or any prospectus supplement;



•

whether we will pay additional amounts on the securities in respect of any tax, assessment or governmental charge and, if so, whether we will have the option to redeem the debt securities instead of making this payment;



•

the subordination provisions, if any, relating to the debt securities; and



•

if the debt securities are to be issued upon the exercise of debt warrants, the time, manner and place for them to be authenticated and delivered.

        We may issue debt securities at less than the principal amount payable at maturity. We refer to these securities as "original issue discount" securities. If material or applicable, we will describe in the applicable prospectus supplement special U.S. federal income tax, accounting and other considerations applicable to original issue discount securities.

        Except as may be described in any prospectus supplement, an indenture will not contain any other provisions that would limit our ability to incur indebtedness or that would afford holders of the debt

3

securities protection in the event of a highly leveraged or similar transaction involving us or in the event of a change of control. You should review carefully the applicable prospectus supplement for information with respect to events of default and covenants applicable to the securities being offered.

Denominations, Interest, Registration and Transfer

        Unless otherwise described in the applicable prospectus supplement, we will issue the debt securities of any series that are registered securities in denominations that are even multiples of $1,000, other than global securities, which may be of any denomination.

        Unless otherwise specified in the applicable prospectus supplement, we will pay the interest, principal and any premium at the corporate trust office of the trustee. At our option, however, we may make payment of interest by check mailed to the address of the person entitled to the payment as it appears in the applicable register or by wire transfer of funds to that person at an account maintained within the United States.

        If we do not punctually pay or otherwise provide for interest on any interest payment date, the defaulted interest will be paid either:

•

to the person in whose name the debt security is registered at the close of business on a special record date the trustee will fix; or



•

in any other lawful manner, all as the applicable indenture describes.

        You may have your debt securities divided into more debt securities of smaller denominations or combined into fewer debt securities of larger denominations, as long as the total principal amount is not changed. We call this an "exchange."

        You may exchange or transfer debt securities at the office of the applicable trustee. The trustee acts as our agent for registering debt securities in the names of holders and transferring debt securities. We may change this appointment to another entity or perform these functions ourselves. The entity performing the role of maintaining the list of registered holders is called the "registrar." The registrar will also perform exchanges and transfers.

        You will not be required to pay a service charge to transfer or exchange debt securities, but you may be required to pay for any tax or other governmental charge associated with the exchange or transfer. The registrar will make the transfer or exchange only if it is satisfied with your proof of ownership.

Merger, Consolidation or Sale of Assets

        Under any indenture, we are generally permitted to consolidate or merge with another entity. We are also permitted to sell substantially all of our assets to another company, or to buy substantially all of the assets of another company. However, we may not take any of these actions unless the following conditions are met:

•

If we merge out of existence or sell all our assets, the other company must be an entity organized under the laws of a state or the District of Columbia or under federal law and must agree to be legally responsible for our debt securities; and



•

Immediately after the merger, sale of assets or other transaction, we may not be in default on our debt securities. A default for this purpose would include any event that would be an event of default if the requirements for giving us default notice or our default having to exist for a specific period of time were disregarded.

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Certain Covenants

        Existence.    Except as permitted as described above under "—Merger, Consolidation or Sale of Assets," we will agree to do all things necessary to preserve and keep our trust existence, rights and franchises provided that it is in our best interests for the conduct of business.

        Provisions of Financial Information.    Whether or not we remain required to do so under the Exchange Act, to the extent permitted by law, we will agree to file all annual, quarterly and other reports and financial statements with the SEC and an indenture trustee on or before the applicable SEC filing dates as if we were required to do so.

        Additional Covenants.    Any additional or different covenants or modifications to the foregoing covenants with respect to any series of debt securities will be described in the applicable prospectus supplement.

Events of Default and Related Matters

        Events of Default.    The term "event of default" for any series of debt securities means any of the following:

•

We do not pay the principal or any premium on a debt security of that series within 30 days after its maturity date;



•

We do not pay interest on a debt security of that series within 30 days after its due date;



•

We do not deposit any sinking fund payment for that series within 30 days after its due date;



•

We remain in breach of any other term of the applicable indenture (other than a term added to the indenture solely for the benefit of other series) for 60 days after we receive a notice of default stating we are in breach. Either the trustee or holders of more than 50% in principal amount of debt securities of the affected series may send the notice;



•

We default under any of our other indebtedness in an aggregate principal amount exceeding a specified dollar amount after the expiration of any applicable grace period, which default results in the acceleration of the maturity of such indebtedness. Such default is not an event of default if the other indebtedness is discharged, or the acceleration is rescinded or annulled, within a period of 10 days after we receive notice specifying the default and requiring that we discharge the other indebtedness or cause the acceleration to be rescinded or annulled. Either the trustee or the holders of more than 50% in principal amount of debt securities of the affected series may send the notice;



•

We or one of our "significant subsidiaries," if any, files for bankruptcy or certain other events in bankruptcy, insolvency or reorganization occur; or



•

Any other event of default described in the applicable prospectus supplement occurs.

        The term "significant subsidiary" means each of our significant subsidiaries, if any, as defined in Regulation S-X under the Securities Act of 1933, as amended, or the Securities Act.

        Remedies if an Event of Default Occurs.    If an event of default has occurred and has not been cured, the trustee or the holders of at least a majority in principal amount of the debt securities of the affected series may declare the entire principal amount of all the debt securities of that series to be due and immediately payable. If an event of default occurs because of certain events in bankruptcy, insolvency or reorganization, the principal amount of all the debt securities of that series will be automatically accelerated, without any action by the trustee or any holder. At any time after the trustee or the holders have accelerated any series of debt securities, but before a judgment or decree for payment of the money due has been obtained, the holders of at least a majority in principal amount of

5

the debt securities of the affected series may, under certain circumstances, rescind and annul such acceleration.

        The trustee will be required to give notice to the holders of debt securities within 90 days after a default under the applicable indenture unless the default has been cured or waived. The trustee may withhold notice to the holders of any series of debt securities of any default with respect to that series, except a default in the payment of the principal of or interest on any debt security of that series, if specified responsible officers of the trustee in good faith determine that withholding the notice is in the interest of the holders.

        Except in cases of default where the trustee has some special duties, the trustee is not required to take any action under the applicable indenture at the request of any holders unless the holders offer the trustee reasonable protection from expenses and liability. We refer to this as an "indemnity." If reasonable indemnity is provided, the holders of a majority in principal amount of the outstanding securities of the relevant series may direct the time, method and place of conducting any lawsuit or other formal legal action seeking any remedy available to the trustee. These majority holders may also direct the trustee in performing any other action under the applicable indenture, subject to certain limitations.

        Before you bypass the trustee and bring your own lawsuit or other formal legal action or take other steps to enforce your rights or protect your interests relating to the debt securities, the following must occur:

•

You must give the trustee written notice that an event of default has occurred and remains uncured;



•

The holders of at least a majority in principal amount of all outstanding securities of the relevant series must make a written request that the trustee take action because of the default, and must offer reasonable indemnity to the trustee against the cost and other liabilities of taking that action; and



•

The trustee must have not taken action for 60 days after receipt of the notice and offer of indemnity.

However, you are entitled at any time to bring a lawsuit for the payment of money due on your security after its due date.

        Every year we will furnish to the trustee a written statement by certain of our officers certifying that to their knowledge we are in compliance with the applicable indenture and the debt securities, or else specifying any default.

Modification of an Indenture

        There are three types of changes we can make to the indentures and the debt securities:

        Changes Requiring Your Approval.    First, there are changes we cannot make to your debt securities without your specific approval. The following is a list of those types of changes:

•

change the stated maturity of the principal or interest on a debt security;



•

reduce any amounts due on a debt security;



•

reduce the amount of principal payable upon acceleration of the maturity of a debt security following a default;



•

change the currency of payment on a debt security;



•

impair your right to sue for payment;

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•

modify the subordination provisions, if any, in a manner that is adverse to you;



•

reduce the percentage of holders of debt securities whose consent is needed to modify or amend an indenture or to waive compliance with certain provisions of an indenture;



•

reduce the percentage of holders of debt securities whose consent is needed to waive past defaults or change certain provisions of the indenture relating to waivers of default;



•

waive a default or event of default in the payment of principal of or premium, if any, or interest on the debt securities; or



•

modify any of the foregoing provisions.

        Changes Requiring a Majority Vote.    The second type of change to an indenture and the debt securities is the kind that requires a vote in favor by holders of debt securities owning a majority of the principal amount of the particular series affected. Most changes fall into this category, except for clarifying changes and certain other changes that would not materially adversely affect holders of the debt securities. We require the same vote to obtain a waiver of a past default. However, we cannot obtain a waiver of a payment default or any other aspect of an indenture or the debt securities listed in the first category described above under "—Changes Requiring Your Approval" unless we obtain your individual consent to the waiver.

        Changes Not Requiring Approval.    The third type of change does not require any vote by holders of debt securities. This type is limited to clarifications and certain other changes that would not materially adversely affect holders of the debt securities.

        Further Details Concerning Voting.    Debt securities are not considered outstanding, and therefore the holders thereof are not eligible to vote if we have deposited or set aside in trust for you money for their payment or redemption or if we or one of our affiliates own them. The holders of debt securities are also not eligible to vote if they have been fully defeased as described immediately below under "—Discharge, Defeasance and Covenant Defeasance—Full Defeasance." For original issue discount securities, we will use the principal amount that would be due and payable on the voting date if the maturity of the debt securities were accelerated to that date because of a default.

Discharge, Full Defeasance and Covenant Defeasance

        Discharge.    We may discharge some obligations to holders of any series of debt securities 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 the trustee, in trust, funds in the applicable currency in an amount sufficient to pay the debt securities, including any premium and interest.

        Full Defeasance.    We can, under particular circumstances, effect a full defeasance of your series of debt securities. By this we mean we can legally release ourselves from any payment or other obligations on the debt securities if, among other things, we put in place the arrangements described below to repay you and deliver certain certificates and opinions to the trustee:

•

We must deposit in trust for your benefit and the benefit of all other direct holders of the debt securities a combination of money or U.S. government agency notes or bonds (or, in some circumstances, depositary receipts representing these notes or bonds) that will generate enough cash to make interest, principal and any other payments on the debt securities on their various due dates;



•

The current federal tax law must be changed or an Internal Revenue Service, or IRS, ruling must be issued permitting the above deposit without causing you to be taxed on the debt securities any differently than if we did not make the deposit and just repaid the debt securities ourselves. Under current federal income tax law, the deposit and our legal release from the debt

7

securities would be treated as though we took back your debt securities and gave you your share of the cash and notes or bonds deposited in trust. In that event, you could recognize gain or loss on the debt securities you give back to us; and

•

We must deliver to the trustee a legal opinion confirming the tax law change or IRS ruling described above.

        If we did accomplish full defeasance, you would have to rely solely on the trust deposit for repayment on the debt securities. You could not look to us for repayment in the unlikely event of any shortfall. Conversely, the trust deposit would most likely be protected from claims of our lenders and other creditors if we ever became bankrupt or insolvent. You would also be released from any subordination provisions.

        Covenant Defeasance.    Under current federal income tax law, we can make the same type of deposit described above and be released from some of the restrictive covenants in the debt securities. This is called "covenant defeasance." In that event, you would lose the protection of those restrictive covenants but would gain the protection of having money and securities set aside in trust to repay the securities and you would be released from any subordination provisions.

        If we accomplish covenant defeasance, the following provisions of an indenture and the debt securities would no longer apply:

•

any covenants applicable to the series of debt securities and described in the applicable prospectus supplement;



•

any subordination provisions; and



•

certain events of default relating to breach of covenants and acceleration of the maturity of other debt set forth in any prospectus supplement.

        If we accomplish covenant defeasance, you can still look to us for repayment of the debt securities if a shortfall in the trust deposit occurred. If one of the remaining events of default occurs, for example, our bankruptcy, and the debt securities become immediately due and payable, there may be a shortfall. Depending on the event causing the default, you may not be able to obtain payment of the shortfall.

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 applicable prospectus supplement. Such terms will include whether the 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, 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 our REIT status under the Internal Revenue Code of 1986, as amended, or the Code.

Subordination

        We will describe in the applicable prospectus supplement the terms and conditions, if any, upon which any series of senior subordinated securities or junior subordinated securities is subordinated to debt securities of another series or to our other indebtedness. The terms will include a description of:

•

the indebtedness ranking senior to the debt securities being offered;



•

the restrictions, if any, on payments to the holders of the debt securities being offered while a default with respect to the senior indebtedness is continuing;

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•

the restrictions, if any, on payments to the holders of the debt securities being offered following an event of default; and



•

provisions requiring holders of the debt securities being offered to remit some payments to holders of senior indebtedness.

Global Securities

        We may issue the debt securities of a series in whole or in part in the form of one or more global securities that will be deposited with a depositary identified in the applicable prospectus supplement. We anticipate that any global securities will be deposited with, or on behalf of, The Depository Trust Company, New York, New York, or DTC, and will be registered in the name of DTC's nominee, and that the following provisions will apply to the depositary arrangements with respect to any global securities. We will describe additional or differing terms of the depositary arrangements in the applicable prospectus supplement relating to a particular series of debt securities issued in the form of global securities.

        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 Federal Reserve System, a "clearing corporation" within the meaning of the New York Uniform Commercial Code and a "clearing agency" registered pursuant to the provisions of Section 17A of the Exchange Act. DTC holds securities that its direct participants deposit with DTC. DTC also facilitates the clearance and settlement among direct participants of securities transactions through electronic computerized book-entry changes in direct participants' accounts. This eliminates the need for physical movement of securities certificates. Direct participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations, some of whom own DTC. Access to DTC's book-entry system is also available to indirect participants, such as securities brokers and dealers, banks and trust companies that clear through or maintain a custodial relationship with a direct participant. The rules applicable to DTC and its participants are on file with the SEC.

        Upon the issuance of a registered global security, DTC will credit, on its book-entry registration and transfer system, the direct participants' accounts with the respective principal or face amounts of the debt securities beneficially owned by the direct participants. Any dealers, underwriters or agents participating in the distribution of the debt securities will designate the accounts to be credited. Ownership of beneficial interests in a registered global security will be shown on, and the transfer of ownership interests will be effected only through, records maintained by DTC, with respect to interests of direct participants, and on the records of direct participants, with respect to interests of persons holding through direct participants.

        So long as DTC or its nominee is the registered owner of a global note, DTC or such nominee, as the case may be, will be considered the sole owner or holder of the debt securities evidenced by a global note for all purposes under the indentures. Except as described below, as an owner of a beneficial interest in debt securities evidenced by a global note you will not be entitled to have any of the debt securities evidenced by such global note registered in your name, you will not receive or be entitled to receive physical delivery of any such debt securities in definitive form and you will not be considered the owner or holder thereof under the indentures 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 indentures. 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 any global note.

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

        Payments of principal and interest or additional amounts, if any, will be made by us to Cede & Co., as nominee of DTC, in immediately available funds and it is our responsibility. DTC's practice is to credit the accounts of direct participants on the applicable payment date in accordance with their respective beneficial interests in the relevant security as shown on the records of DTC. Payments by direct participants to the beneficial owners of debt securities will be governed by standing instructions and customary practices, as is the case with securities held for the accounts of customers in bearer form or registered in "street name," and will be the responsibility of DTC's direct participants. Payment to Cede & Co. is our responsibility. Disbursement of such payments to direct participants is the responsibility of DTC. Disbursement of such payments to the beneficial owners is the responsibility of direct and indirect participants. Redemption notices with respect to any debt securities will be sent to DTC. If less than all of the debt securities are to be redeemed, DTC's practice is to determine by lot the amount of interest of each direct participant in such issue to be redeemed.

        Neither we nor the trustee nor any other agent of ours or any agent of the trustee will have any responsibility or liability for any aspect of the records relating to payments made on account of beneficial ownership interests in the registered global security or for maintaining, supervising or reviewing any records relating to those beneficial ownership interests.

        Neither DTC nor Cede & Co. (nor any other DTC nominee) will consent to vote with respect to the debt securities unless authorized by a direct participant in accordance with DTC's procedures. Under its usual procedures, DTC would mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns Cede & Co.'s consenting or voting rights to those direct participants to whose accounts debt securities are credited on the record date (identified in a listing attached to the omnibus proxy). 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 indentures, 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.

        Debt securities which are evidenced by a global note will be exchangeable for certified debt securities with the same terms in authorized denominations only if:

•

DTC notifies us that it is unwilling or unable to continue as depositary or if DTC ceases to be a clearing agency registered under applicable law and a successor depositary is not appointed within 90 days;



•

there shall have occurred and be continuing an event of default; or



•

we determine not to require all of the debt securities to be evidenced by a global note and notify the trustee of our decision, in which case we will issue individual debt securities in denominations of $1,000 and integral multiples thereof.

        The information in this prospectus concerning DTC and DTC's book-entry system has been obtained from sources that we believe to be reliable, but we take no responsibility for its accuracy or completeness. We assume no responsibility for the performance by DTC or its participants of their respective obligations, including obligations that they have under the rules and procedures that govern their operations.

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DESCRIPTION OF SHARES OF BENEFICIAL INTEREST

        Our declaration of trust authorizes us to issue up to an aggregate of 50,000,000 shares of beneficial interest, consisting of 50,000,000 common shares of beneficial interest, $.01 par value per share, or common shares. As of June 30, 2010, we had 31,263,850 common shares issued and outstanding. As of the date of this prospectus, no other class or series of shares of beneficial interest has been established.

        As permitted by the Maryland REIT law, our declaration of trust authorizes our board of trustees, or board, to increase or decrease the number of our authorized common shares, to create new classes or series of shares, to increase or decrease the number of any class of shares and to classify or reclassify any unissued shares from time to time by setting or changing the preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms and conditions of redemption of shares.

        Our board may take the actions described above without shareholder approval, unless shareholder approval is required by applicable law or the rules of the principal stock exchange on which our securities may be listed, which currently is the NYSE. We believe that the ability of our board to authorize and issue one or more classes or series of shares with specified preferences will provide us with flexibility in structuring possible future financings and acquisitions and in meeting other business needs that may arise. Although our board has no intention at the present time of doing so, it could authorize us to issue a class or series that could, depending upon the terms of the class or series, delay or prevent a change in control.

Common Shares

        The following is a summary of the material terms of our common shares. Because it is a summary, it does not contain all of the information that may be important to you. If you want more information, you should read our declaration of trust and bylaws, copies of which have been filed with the SEC. See "Where You Can Find More Information." This summary is also subject to and qualified by reference to the description of the particular terms of your securities described in the applicable prospectus supplement.

        Except as otherwise described in any applicable prospectus supplement, holders of our common shares are entitled to the following, subject to the preferential rights of any other class or series of shares which may be issued in the future and to the provisions of our declaration of trust regarding the restriction on the transfer and ownership of shares of beneficial interest:

•

to receive distributions on their common shares if, as and when authorized by our board and declared by us out of assets legally available for distribution as long as they hold their common shares on the applicable record date for any distribution; and



•

to share ratably in our assets legally available for distribution to our shareholders in the event of our liquidation, dissolution or winding up after payment of or adequate provision for all of our known debts and liabilities.

        Under our declaration of trust, holders of our common shares are entitled to vote on the following matters: (a) election of trustees and the removal of trustees for cause; (b) amendment of our declaration of trust (provided that certain amendments of our declaration of trust are permitted under the Maryland REIT law to be authorized by our board without shareholder approval); (c) our termination; (d) to the extent required by Maryland law, our merger, consolidation, or the sale or disposition of substantially all of our property; and (e) such other matters with respect to which our board has adopted a resolution declaring that a proposed action is advisable and directing that the matter be submitted to the shareholders for approval or ratification. Holders of our common shares are also entitled to vote on such matters as may be required by applicable law or the rules of the principal exchange on which our common shares are listed, which is currently the NYSE.

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        Holders of our common shares have no preference, conversion, exchange, sinking fund, redemption or appraisal rights. Holders of our common shares have no preemptive rights to subscribe for any of our securities.

        For other information with respect to our common shares, including effects that provisions in our declaration of trust and bylaws may have in delaying, deferring or preventing a change in our control, see "Material Provisions of Maryland Law and our Declaration of Trust and Bylaws" below.

Preferred Shares

        The following describes some general terms and provisions of the preferred shares to which a prospectus supplement may relate. 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 our declaration of trust, including any applicable articles supplementary, and our bylaws.

        Our declaration of trust authorizes our board to classify from time to time any unissued shares of beneficial interest in one or more classes or series of preferred shares and to reclassify any previously classified but unissued preferred shares of any class or series, in one or more classes or series, and to determine the preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms and conditions of redemption of any such class or series of preferred shares. These may include:

•

the distinctive designation of each series and the number of shares that will constitute the series;



•

the voting rights, if any, of shares of the series;



•

the distribution rate on the shares of the series, any restriction, limitation or condition upon the payment of the distribution, whether distributions will be cumulative, and the dates on which distributions accumulate and are payable;



•

the prices at which, and the terms and conditions on which, the shares of the series may be redeemed, if the shares are redeemable;



•

the purchase or sinking fund provisions, if any, for the purchase or redemption of shares of the series;



•

any preferential amount payable upon shares of the series upon our liquidation or the distribution of our assets;



•

if the shares are convertible, the price or rates of conversion at which, and the terms and conditions on which, the shares of the series may be converted into other securities; and



•

whether the series can be exchanged, at our option, into debt securities, and the terms and conditions of any permitted exchange.

        The issuance of preferred shares, or the issuance of rights to purchase preferred shares, could discourage an unsolicited acquisition proposal. In addition, the rights of holders of common shares will be subject to, and may be adversely affected by, the rights of holders of any preferred shares that we may issue in the future.

        The prospectus supplement will describe the specific terms as to each issuance of preferred shares, including:

•

the description of the preferred shares;



•

the number of the preferred shares offered;



•

the voting rights, if any, of the holders of the preferred shares;



•

the offering price of the preferred shares;

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•

the distribution rate, when distributions will be paid, or the method of determining the distribution rate if it is based on a formula or not otherwise fixed;



•

the date from which distributions on the preferred shares shall accumulate;



•

the provisions for any auctioning or remarketing, if any, of the preferred shares;



•

the provision, if any, for redemption or a sinking fund;



•

the liquidation preference per share;



•

any listing of the preferred shares on a securities exchange;



•

whether the preferred shares will be convertible and, if so, the security into which they are convertible and the terms and conditions of conversion, including the conversion price or the manner of determining it;



•

whether interests in the preferred shares will be represented by depositary shares as more fully described below under "Description of Depositary Shares";



•

a discussion of federal income tax considerations;



•

the relative ranking and preferences of the preferred shares as to distribution and liquidation rights;



•

any limitations on issuance of any preferred shares ranking senior to or on a parity with the series of preferred shares being offered as to distribution and liquidation rights;



•

any limitations on direct or beneficial ownership and restrictions on transfer, in each case as may be appropriate to preserve our status as a REIT; and



•

any other specific preferences, conversion or other rights, voting powers, restrictions, limitations as to dividends or other distributions, qualifications and terms and conditions of redemption of the preferred shares.

        As described under "Description of Depositary Shares," we may, at our option, elect to offer depositary shares evidenced by depositary receipts. If we elect to do this, each depositary receipt will represent a fractional interest in a share of the particular series of the preferred shares issued and deposited with a depositary. The applicable prospectus supplement will specify that fractional interest.

Rank

        Unless our board otherwise determines and we so specify in the applicable prospectus supplement, we expect that the preferred shares will, with respect to distribution rights and rights upon liquidation or dissolution, rank senior to all our common shares.

Distributions

        Holders of preferred shares of each series will be entitled to receive cash and/or share distributions at the rates and on the dates shown in the applicable prospectus supplement. Even though the preferred shares may specify a fixed rate of distribution, our board must authorize and we must declare those distributions and they may be paid only out of assets legally available for payment. We will pay each distribution to holders of record as they appear on our share transfer books on the record dates fixed by our board. In the case of preferred shares represented by depositary receipts, the records of the depositary referred to under "Description of Depositary Shares" will determine the persons to whom distributions are payable.

        Distributions on any series of preferred shares may be cumulative or noncumulative, as provided in the applicable prospectus supplement. We refer to each particular series, for ease of reference, as the applicable series. Cumulative distributions will be cumulative from and after the date shown in the

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applicable prospectus supplement. If our board fails to authorize a distribution on any applicable series that is noncumulative, the holders will have no right to receive, and we will have no obligation to pay, a distribution in respect of the applicable distribution period, whether or not distributions on that series are declared payable in the future.

        If the applicable series is entitled to a cumulative distribution, we may not declare, or pay or set aside for payment, any full distributions on any other series of preferred shares ranking, as to distributions, on a parity with or junior to the applicable series, unless we declare, and either pay or set aside for payment, full cumulative distributions on the applicable series for all past distribution periods and the then current distribution period. If the applicable series does not have a cumulative distribution, we must declare, and pay or set aside for payment, full distributions for the then current distribution period only. When distributions are not paid, or set aside for payment, in full upon any applicable series and the shares of any other series ranking on a parity as to distributions with the applicable series, we must declare, and pay or set aside for payment, all distributions upon the applicable series and any other parity series proportionately, in accordance with accrued and unpaid distributions of the several series. For these purposes, accrued and unpaid distributions do not include unpaid distribution periods on noncumulative preferred shares. No interest will be payable in respect of any distribution payment that may be in arrears.

        Except as provided in the immediately preceding paragraph, unless we declare, and pay or set aside for payment, full cumulative distributions, including for the then current period, on any cumulative applicable series, we may not declare, or pay or set aside for payment, any distributions upon common shares or any other equity securities ranking junior to or on a parity with the applicable series as to distributions or upon liquidation. The foregoing restriction does not apply to distributions paid in common shares or other equity securities ranking junior to the applicable series as to distributions and upon liquidation. If the applicable series is noncumulative, we need only declare, and pay or set aside for payment, the distribution for the then current period, before declaring distributions on common shares or junior or parity securities. In addition, under the circumstances that we could not declare a distribution, we may not redeem, purchase or otherwise acquire for any consideration any common shares or other parity or junior equity securities, except upon conversion into or exchange for common shares or other junior equity securities. We may, however, make purchases and redemptions otherwise prohibited pursuant to certain redemptions or pro rata offers to purchase the outstanding shares of the applicable series and any other parity series of preferred shares.

        We will credit any distribution payment made on an applicable series first against the earliest accrued but unpaid distribution due with respect to the series.

Redemption

        We may have the right or may be required to redeem one or more series of preferred shares, as a whole or in part, in each case upon the terms, if any, and at the times and at the redemption prices shown in the applicable prospectus supplement.

        If a series of preferred shares is subject to mandatory redemption, we will specify in the applicable prospectus supplement the number of shares we are required to redeem, when those redemptions start, the redemption price, and any other terms and conditions affecting the redemption. The redemption price will include all accrued and unpaid distributions, except in the case of noncumulative preferred shares. 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 our issuance of shares of beneficial interest, the terms of the preferred shares may provide that, if no shares of beneficial interest 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, the preferred shares will automatically and mandatorily be converted into shares of beneficial interest pursuant to conversion provisions specified in the applicable prospectus supplement.

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Liquidation Preference

        The applicable prospectus supplement will show the liquidation preference of the applicable series. Upon our voluntary or involuntary liquidation, before any distribution may be made to the holders of our common shares or any other shares of beneficial interest ranking junior in the distribution of assets upon any liquidation to the applicable series, the holders of that series will be entitled to receive, out of our assets legally available for distribution to shareholders, liquidating distributions in the amount of the liquidation preference, plus an amount equal to all distributions accrued and unpaid. In the case of a noncumulative applicable series, accrued and unpaid distributions include only the then current distribution period. 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 our remaining assets. If liquidating distributions shall have been made in full to all holders of preferred shares, our remaining assets will be distributed among the holders of any other shares of beneficial interest ranking junior to the preferred shares upon liquidation, according to their rights and preferences and in each case according to their number of shares.

        If, upon any voluntary or involuntary liquidation, our available assets are insufficient to pay the amount of the liquidating distributions on all outstanding shares of that series and the corresponding amounts payable on all shares of beneficial interest ranking on a parity in the distribution of assets with that series, then the holders of that series and all other equally ranking shares of beneficial interest shall share ratably in the distribution in proportion to the full liquidating distributions to which they would otherwise be entitled.

        For these purposes, our consolidation or merger with or into any other trust or corporation or other entity, or the sale, lease or conveyance of all or substantially all of our property or business, will not be a liquidation.

Voting Rights

        Holders of our preferred shares will not have any voting rights, except as shown below or as otherwise from time to time specified in the applicable prospectus supplement.

        Unless otherwise specified in the applicable prospectus supplement, holders of our preferred shares (voting separately as a class with all other series of preferred shares with similar voting rights) will be entitled to elect two additional trustees to our board at our next annual meeting of shareholders and at each subsequent annual meeting if at any time distributions on the applicable series are in arrears for six consecutive quarterly periods. If the applicable series has a cumulative distribution, the right to elect additional trustees described in the preceding sentence shall remain in effect until we declare or pay and set aside for payment all distributions accrued and unpaid on the applicable series. If the applicable series does not have a cumulative distribution, the right to elect additional trustees described above shall remain in effect until we declare or pay and set aside for payment distributions accrued and unpaid on four consecutive quarterly periods on the applicable series. In the event the preferred shareholders are so entitled to elect trustees, the entire board will be increased by two trustees.

        Unless otherwise provided for in an applicable series, so long as any preferred shares are outstanding, we may not, without the affirmative vote or consent of a majority of the shares of each series of preferred shares outstanding at that time:

•

authorize, create or increase the authorized or issued amount of any class or series of shares of beneficial interest ranking senior to that series of preferred shares with respect to distribution and liquidation rights;

15

•

reclassify any authorized shares of beneficial interest into a series of shares of beneficial interest ranking senior to that series of preferred shares with respect to distribution and liquidation rights;



•

create, authorize or issue any security or obligation convertible into or evidencing the right to purchase any shares of beneficial interest ranking senior to that series of preferred shares with respect to distribution and liquidation rights; and



•

amend, alter or repeal the provisions of our declaration of trust or any articles supplementary relating to that series of preferred shares, whether by merger consolidation or otherwise, that materially and adversely affects the series of preferred shares.

        The authorization, creation or increase of the authorized or issued amount of any class or series of shares of beneficial interest ranking on parity or junior to a series of preferred shares with respect to distribution and liquidation rights will not be deemed to materially and adversely affect that series.

        The foregoing voting provisions will not apply if all of the outstanding shares of the series of preferred shares with the right to vote have been redeemed or called for redemption and sufficient funds have been deposited in trust for the redemption either at or prior to the act triggering these voting rights.

        As more fully described under "Description of Depositary Shares" below, if we elect to issue depositary shares, each representing a fraction of a share of a series, each depositary will in effect be entitled to a fraction of a vote per depositary share.

Conversion Rights

        We will describe in the applicable prospectus supplement the terms and conditions, if any, upon which you may, or we may require you to, convert shares of any series of preferred shares into common shares or any other class or series of shares of beneficial interest. The terms will include the number of common shares or other securities into which the preferred shares are convertible, the conversion price (or the manner of determining it), the conversion period, provisions as to whether conversion will be at the option of the holders of the series or at our option, the events requiring an adjustment of the conversion price, and provisions affecting conversion upon the redemption of shares of the series.

Our Exchange Rights

        We will describe in the applicable prospectus supplement the terms and conditions, if any, upon which we can require you to exchange shares of any series of preferred shares for debt securities. If an exchange is required, you will receive debt securities with a principal amount equal to the liquidation preference of the applicable series of preferred shares. The other terms and provisions of the debt securities will not be materially less favorable to you than those of the series of preferred shares being exchanged.

DESCRIPTION OF DEPOSITARY SHARES

General

        The following is a summary of the material provisions of any deposit agreement and of the depositary shares and depositary receipts representing depositary shares. Because it is a summary, it does not contain all of the information that may be important to you. If you want more information, you should read the form of deposit agreement and depositary receipts which will be filed as exhibits to the registration statement of which this prospectus is a part prior to an offering of depositary shares. See "Where You Can Find More Information." This summary is also subject to and qualified by

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reference to the descriptions of the particular terms of your securities described in the applicable prospectus supplement.

        We may, at our option, elect to offer fractional interests in shares of preferred shares, rather than shares of preferred shares. If we exercise this option, we will appoint a depositary to issue depositary receipts representing those fractional interests. Preferred shares of each series represented by depositary shares will be deposited under a separate deposit agreement between us and the depositary. The prospectus supplement relating to a series of depositary shares will show the name and address of the depositary. Subject to the terms of the applicable deposit agreement, each owner of depositary shares will be entitled to all of the distribution, voting, conversion, redemption, liquidation and other rights and preferences of the preferred shares represented by those depositary shares.

        Depositary receipts issued pursuant to the applicable deposit agreement will evidence ownership of depositary shares. Upon surrender of depositary receipts at the office of the depositary, and upon payment of the charges provided in and subject to the terms of the deposit agreement, a holder of depositary shares will be entitled to receive the preferred shares underlying the surrendered depositary receipts.

Distributions

        A depositary will be required to distribute all 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 depositary receipts owned by the holders. Fractions will be rounded down to the nearest whole cent.

        If the distribution is other than in cash, a depositary will be required to distribute property received by it to the record holders of depositary receipts entitled thereto, unless the depositary determines that it is not feasible to make the distribution. In that case, the depositary may, with our approval, sell the property and distribute the net proceeds from the sale to the holders.

        Depositary shares that represent preferred shares converted or exchanged will not be entitled to distributions. The deposit agreement will also contain provisions relating to the manner in which any subscription or similar rights we offer to holders of the preferred shares will be made available to holders of depositary shares. All distributions will be subject to obligations of holders to file proofs, certificates and other information and to pay certain charges and expenses to the depositary.

Withdrawal of Preferred Shares

        You may receive the number of whole shares of your series of preferred shares and any money or other property represented by those depositary receipts after surrendering the depositary receipts at the corporate trust office of the depositary. Partial shares of preferred shares will not be issued. If the depositary shares that you surrender exceed the number of depositary shares that represent the number of whole preferred shares you wish to withdraw, then the depositary will deliver to you at the same time a new depositary receipt evidencing the excess number of depositary shares. Once you have withdrawn your preferred shares, you will not be entitled to re-deposit those preferred shares under the deposit agreement in order to receive depositary shares. We do not expect that there will be any public trading market for withdrawn preferred shares.

Redemption of Depositary Shares

        If we redeem a series of the preferred shares underlying the depositary shares, the depositary will redeem those shares from the proceeds received by it. The depositary will mail notice of redemption not less than 30 and not more than 60 days before the date fixed for redemption to the record holders of the depositary receipts evidencing the depositary shares we are redeeming at their addresses

17

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 the series of the preferred shares. The redemption date for depositary shares will be the same as that of the preferred shares. If we are redeeming less than all of the depositary shares, the depositary will select the depositary shares we are redeeming by lot or pro rata as the depositary may determine.

        After the date fixed for redemption, the depositary shares called for redemption will no longer be deemed outstanding. All rights of the holders of the depositary shares and the related depositary receipts will cease at that time, except the right to receive the money or other property to which the holders of depositary shares were entitled upon redemption. Receipt of the money or other property is subject to surrender to the depositary of the depositary receipts evidencing the redeemed 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 the notice of meeting to the record holders of the applicable depositary receipts. Each record holder of depositary receipts on the record date, which will be the same date as the record date, will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the amount of preferred shares represented by the holder's depositary shares. The depositary will try, as practical, to vote the shares as you instruct. We will agree to take all reasonable action that the depositary deems necessary in order to enable it to do so. If you do not instruct the depositary how to vote your shares, the depositary will abstain from voting those shares. The depositary will not be responsible for any failure to carry out an instruction to vote or for the effect of any such vote made so long as the action or inaction of the depositary is in good faith and is not the result of the depositary's gross negligence or willful misconduct.

Liquidation Preference

        Upon our liquidation, whether voluntary or involuntary, each holder of depositary shares will be entitled to the fraction of the liquidation preference accorded each preferred share represented by the depositary shares, as shown in the applicable prospectus supplement.

Conversion or Exchange of Preferred Shares

        The depositary shares will not themselves be convertible into or exchangeable for common shares, preferred shares or any of our other securities or property. Nevertheless, if so specified in the applicable prospectus supplement, the depositary receipts may be surrendered by holders to the applicable depositary with written instructions to it to instruct us to cause conversion of the preferred shares represented by the depositary shares. Similarly, if so specified in the applicable prospectus supplement, we may require you to surrender all of your depositary receipts to the applicable depositary upon our requiring the conversion or exchange of the preferred shares represented by the depositary shares into our debt securities. We will agree that, upon receipt of the instruction and any amounts payable in connection with the conversion or exchange, we will cause the conversion or exchange using the same procedures as those provided for delivery of preferred shares to effect the conversion or exchange. If you are converting only a part of the depositary shares, the depositary will issue you a new depositary receipt for any unconverted depositary shares.

Taxation

        As owner of depositary shares, you will be treated for U.S. federal income tax purposes as if you were an owner of the series of preferred shares represented by the depositary shares. Therefore, you

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will be required to take into account for U.S. federal income tax purposes income and deductions to which you would be entitled if you were a holder of the underlying series of preferred shares. In addition:

•

no gain or loss will be recognized for U.S. federal income tax purposes upon the withdrawal of preferred shares in exchange for depositary shares provided in the deposit agreement;



•

the tax basis of each preferred share to you as exchanging owner of depositary shares will, upon exchange, be the same as the aggregate tax basis of the depositary shares exchanged for the preferred shares; and



•

if you held the depositary shares as a capital asset at the time of the exchange for preferred shares, the holding period for the preferred shares will include the period during which you owned the depositary shares.

Amendment and Termination of a Deposit Agreement

        We and the applicable depositary are permitted to amend the provisions of the depositary receipts and the deposit agreement. However, the holders of at least a majority of the applicable depositary shares then outstanding must approve any amendment that adds or increases fees or charges or prejudices an important right of holders. Every holder of an outstanding depositary receipt at the time any amendment becomes effective, by continuing to hold the receipt, will be bound by the applicable deposit agreement, as amended.

        Any deposit agreement may be terminated by us upon not less than 30 days' prior written notice to the applicable depositary if (1) the termination is necessary to preserve our status as a Maryland REIT or (2) a majority of each series of preferred shares affected by the termination consents to the termination. When either event occurs, the depositary will be required to deliver or make available to each holder of depositary receipts, upon surrender of the depositary receipts held by the holder, the number of whole or fractional shares of preferred shares as are represented by the depositary shares evidenced by the depositary receipts, together with any other property held by the depositary with respect to the depositary receipts. In addition, a deposit agreement will automatically terminate if:

•

all depositary shares have been redeemed;



•

there shall have been a final distribution in respect of the related preferred shares in connection with our liquidation and the distribution has been made to the holders of depositary receipts evidencing the depositary shares underlying the preferred shares; or



•

each related preferred share shall have been converted or exchanged into securities not represented by depositary shares.

Charges of a Depositary

        We will pay all transfer and other taxes and governmental charges arising solely from the existence of a deposit agreement. In addition, we 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 the holders request to be performed that 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 us notice of its election to do so. In addition, we may at any time remove a depositary. Any resignation or removal will take effect when we appoint a successor depositary and it accepts the appointment. We must appoint a successor depositary within

19

60 days after delivery of the notice of resignation or removal. A depositary must be a bank or trust company having its principal office in the United States that has 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 us that it receives with respect to the related preferred shares. Holders of depositary receipts will be able to inspect the transfer books of the depositary and the list of holders of depositary receipts upon reasonable notice.

        Neither a depositary nor our company will be liable if it is prevented from or delayed in performing its obligations under a deposit agreement by law or any circumstances beyond its control. Our obligations and those of the depositary under a deposit agreement will be limited to performing duties in good faith and without gross negligence or willful misconduct. Neither we nor any depositary will be obligated to prosecute or defend any legal proceeding in respect of any depositary receipts, depositary shares or related preferred shares unless satisfactory indemnity is furnished. We and each depositary will be permitted to rely on written advice of counsel or accountants, on information provided by persons presenting preferred shares for deposit, by holders of depositary receipts, or by other persons believed in good faith to be competent to give the information, and on documents believed in good faith to be genuine and signed by a proper party.

        If a depositary receives conflicting claims, requests or instructions from any holders of depositary receipts, on the one hand, and us, on the other hand, the depositary shall be entitled to act on the claims, requests or instructions received from us.

DESCRIPTION OF WARRANTS

        The following is a summary of the material terms of our warrants and the warrant agreement. Because it is a summary, it does not contain all of the information that may be important to you. If you want more information, you should read the forms of warrants and the warrant agreement which will be filed as exhibits to the registration statement of which this prospectus is a part. See "Where You Can Find More Information." This summary is also subject to and qualified by reference to the descriptions of the particular terms of our securities described in the applicable prospectus supplement.

        We may issue, together with any other securities being offered or separately, warrants entitling the holder to purchase from or sell to us, or to receive from us the cash value of the right to purchase or sell, debt securities, preferred shares, depositary shares or common shares. We and a warrant agent will enter a warrant agreement pursuant to which the warrants will be issued. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants. We will file a copy of the forms of warrants and the warrant agreement with the SEC at or before the time of the offering of the applicable series of warrants.

        In the case of each series of warrants, the applicable prospectus supplement will describe the terms of the warrants being offered thereby. These include the following, if applicable:

•

the offering price;



•

the currencies in which such warrants are being offered;



•

the number of warrants offered;



•

the securities underlying the warrants;

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•

the exercise price, the procedures for exercise of the warrants and the circumstances, if any, that will cause the warrants to be automatically exercised;



•

the date on which the warrants will expire;



•

federal income tax considerations;



•

the rights, if any, we have to redeem the warrants;



•

the name of the warrant agent; and



•

the 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. Before the exercise of warrants, holders will not have any of the rights of holders of the securities purchasable upon exercise and will not be entitled to payments made to holders of those securities.

        The warrant agreement may be amended or supplemented without the consent of the holders of the warrants to which the amendment or supplement applies 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. However, any amendment that materially and adversely alters the rights of the holders of warrants will not be effective unless the holders of at least a majority of the applicable warrants then outstanding approve the amendment. Every holder of an outstanding warrant at the time any amendment becomes effective, by continuing to hold the warrant, will be bound by the applicable warrant agreement as amended thereby. The prospectus supplement applicable to a particular series of warrants may provide that certain provisions of the warrants, including the securities for which they may be exercisable, the exercise price, and the expiration date may not be altered without the consent of the holder of each warrant.

MATERIAL PROVISIONS OF MARYLAND LAW
AND OF OUR DECLARATION OF TRUST AND BYLAWS

        We were organized as a perpetual life Maryland REIT. The following is a summary of our declaration of trust and bylaws, as currently in effect, and several provisions of Maryland law. Because it is a summary, it does not contain all the information that may be important to you. If you want more information, you should read our declaration of trust and bylaws, copies of which we have previously filed with the SEC, or refer to the provisions of Maryland law.

Trustees

        Our declaration of trust and bylaws provide for a board of trustees of five members and that our board may change the number of trustees, but there may not be less than three trustees.

        Our declaration of trust divides our board into three classes. Shareholders elect our trustees of each class for three year terms upon expiration of their current terms. Shareholders elect only one class of trustees each year. We believe that classification of our board helps to assure the continuity of our business strategies and policies. The classified board provision could have the effect of making the replacement of incumbent trustees more time consuming and difficult. At least two annual meetings of shareholders will generally be required to effect a change in a majority of our board.

        There is no cumulative voting in the election of trustees. Except as may be mandated by any applicable law or the listing requirements of the principal exchange on which our common shares are listed, which is currently the NYSE, and subject to the voting rights of any class or series of our shares of beneficial interest which may be hereafter created, (a) a majority of all the votes cast at a meeting of shareholders duly called and at which a quorum is present is required to elect a trustee in an

21

uncontested election of trustees and (b) a majority of all the votes entitled to be cast in the election of trustees at a meeting of shareholders duly called and at which a quorum is present is required to elect a trustee in a contested election (which is an election at which the number of nominees exceeds the number of trustees to be elected).

        In case of failure to elect trustees at an annual meeting of the shareholders, the incumbent trustees will hold over and continue to direct the management of our business and affairs. In the event of a vacancy on our board, including a vacancy caused by a resignation of a trustee or by an increase in the number of trustees, the remaining trustees may by majority vote elect a new trustee to fill the vacancy for the remaining term in which the vacancy exists. Our declaration of trust provides that a trustee may be removed (1) only for cause, at a meeting of shareholders properly called for that purpose, by the affirmative vote of at least 75% of the outstanding shares entitled to be cast in the election of trustees, or (2) with or without cause, by the affirmative vote of not less than 75% of the remaining trustees. This precludes shareholders from removing incumbent trustees unless they can obtain a substantial affirmative vote of shares.

        Under our bylaws, a trustee must be 21 years of age, not under legal disability, have substantial expertise or experience relevant to our business (as determined by our board), not have been convicted of a felony and meet the qualifications of an "Independent Trustee" or a "Managing Trustee." An "Independent Trustee" is one who is not an employee of our manager, Reit Management & Research LLC, or RMR, who is not involved in our day to day activities and who meets the qualifications of an independent director under the applicable rules of the principal stock exchange upon which our common shares are listed for trading and the SEC, as those requirements may be amended from time to time. A "Managing Trustee" is one who has been an employee, officer or director of our manager or involved in our day to day activities for at least one year prior to his or her election. A majority of the trustees holding office shall at all times be Independent Trustees, except for temporary periods due to vacancies. If the number of trustees, at any time, is set at less than five, at least one trustee will be a Managing Trustee. So long as the number of trustees shall be five or greater, at least two trustees will be Managing Trustees.

Advance Notice of Trustee Nominations and New Business

        Annual Meetings of Shareholders.    Our bylaws provide that nominations of individuals for election to our board and proposals of other business to be considered at an annual meeting of shareholders may be made only in our notice of the meeting, by or at the direction of our board, or by a shareholder who is entitled to vote at the meeting, is entitled to make nominations or proposals and has complied with the advance notice procedures set forth in our bylaws.

        Under our bylaws, a shareholder's written notice of nominations for trustee or other matters to be considered at an annual meeting of shareholders must be delivered to our Secretary at our principal executive offices not later than 5:00 p.m. (Eastern Time) on the 120th day nor earlier than the 150th day prior to the first anniversary of the date of our proxy statement for the preceding year's annual meeting; provided however, that in the event that the date of the proxy statement for the annual meeting is more than 30 days earlier than the first anniversary of the date of the proxy statement for the preceding year's annual meeting, the notice must be delivered by not later than 5:00 p.m. (Eastern Time) on the 10th day following the earlier of the day on which (1) notice of the annual meeting is mailed or otherwise made available or (2) public announcement of the date of such meeting is first made by us.

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        Our bylaws set forth procedures for submission of nominations for trustee elections and other proposals by shareholders for consideration at an annual meeting of shareholders, including, among other things:

•

requiring that a shareholder wishing to make a nomination or proposal of other business to be a shareholder of record of at least $2,000 in market value, or 1% of our shares of beneficial interest, entitled to make nominations or propose other business and to vote at the meeting on such election or proposal for other business, as the case may be, for at least one year immediately preceding such shareholder's submission of a notice of nomination or proposal of other business, that the shareholder continue to be a shareholder of record at the time of submitting its notice of a nomination or other proposal through and including the time of the annual meeting and that the shareholder submit the nomination or proposal of other business to our Secretary in accordance with our bylaws;



•

providing that the advance notice provisions in our bylaws are the exclusive means for a shareholder to make nominations or propose business for consideration at an annual meeting of shareholders, except to the extent of matters which are required to be presented to shareholders by applicable law which have been properly presented in accordance with the requirements of such law;



•

requiring information be provided regarding any proposed nominee by the proposing shareholder, including, among other things:



•

the name, age, business address and residence address of the proposed nominee;



•

information as to the proposed nominee's qualifications to be an Independent or Managing Trustee pursuant to the criteria set forth in the bylaws;



•

the class, series and number of any shares that are, directly or indirectly, beneficially owned or owned of record by the proposed nominee, and the date such shares were acquired and the investment intent of such acquisition;



•

a description of all purchases and sales of our securities and all Derivative Transactions (as defined in our bylaws) by such proposed nominee during the previous 12 months, including the date of the transactions, the class, series and number of securities involved in the transactions and the consideration involved;



•

disclosure of certain performance related fees to which the proposed nominee is entitled, that are based on any increase or decrease in the value of our shares or instrument or arrangement of the type contemplated within the definition of a Derivative Transaction, if any, as of the date of such notice;



•

disclosure of any proportionate interest in our shares or instrument or arrangement of the type contemplated within the definition of a Derivative Transaction that is held, directly or indirectly, by a general or limited partnership in which such proposed nominee is a general partner or, directly or indirectly, beneficially owns an interest in a general partner;



•

disclosure of any other material relationships between or among the proposing shareholder, the proposed nominee or others acting in concert with the proposing shareholder or proposed nominee, including, without limitation, all information that would be required to be disclosed pursuant to Item 404 of Regulation S-K promulgated by the SEC if the shareholder making the nomination or any person acting in concert with the shareholder were the "registrant" for purposes of such rule and the proposed nominee were a director or executive officer of such registrant; and

23

•

all other information relating to the proposed nominee that is required to be disclosed in solicitations of proxies for election of a trustee in an election contest (even if an election contest is not involved), or is otherwise required, in each case, pursuant to Section 14 (or any successor provision) of the Exchange Act;



•

requiring information be provided with respect to any business other than the election of trustees that a shareholder proposes to bring before a meeting of shareholders, including:



•

a description of the business;



•

the reasons for proposing the business and any material interest in the business of such shareholder, including any anticipated benefit to the shareholder;



•

a description of all agreements, arrangements and understandings between the shareholder and any other person or persons (including their names) in connection with the proposal of such business by the shareholder; and



•

a representation that the shareholder intends to appear in person or by proxy at the meeting to bring the business before the meeting;



•

requiring information to be provided as to the shareholder giving the notice and certain of its affiliates, including:



•

the name and address of the shareholder as they appear on our share ledger;



•

the class, series and number of, and the nominee holder for, any of our shares that are owned, directly or indirectly, beneficially or of record by the shareholder or by certain of its affiliates, and the date such shares were acquired and the investment intent of such acquisition;



•

a description of all purchases and sales of our securities and all Derivative Transactions by such shareholder and certain of its affiliates during the previous 12 months, including the date of the transactions, the class, series and number of securities involved in the transactions and the consideration involved;



•

disclosure of certain performance related fees that the shareholder or certain affiliates of the shareholder are entitled to based on any increase or decrease in the value of our shares or instrument or arrangement of the type contemplated within the definition of Derivative Transaction, if any, as of the date of such notice;



•

disclosure of any proportionate interest in our shares or instrument or arrangement of the type contemplated within the definition of Derivative Transaction held, directly or indirectly, by a general or limited partnership in which the shareholder or certain affiliates of the shareholder is a general partner or, directly or indirectly, beneficially owns an interest in a general partner; and



•

all other information relating to the shareholder required to be disclosed in connection with the solicitation of proxies for election of trustees in an election contest (even if an election contest is not involved), or is otherwise required, in each case, pursuant to Section 14 (or any successor provision) of the Exchange Act, and the rules and regulations promulgated thereunder; and



•

providing that the proposing shareholder is responsible for ensuring compliance with the advance notice provisions, that any responses of the shareholder to any request for information will not cure any defect in the shareholder's notice and that neither we, our board, any committee of our board nor any of our officers has any duty to request clarification or updating information or inform the proposing shareholder of any defect in the shareholder's notice.

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        Special Meetings of Shareholders.    With respect to special meetings of shareholders, our bylaws provide that only business brought before the meeting pursuant to our notice of the meeting may be conducted at such meeting. Nominations of individuals for election to our board may be made at a special meeting of shareholders at which trustees are to be elected pursuant to our notice of meeting, by or at the direction of our board, or, provided that our board has determined that trustees will be elected at such special meeting, by a shareholder who is entitled to vote at the meeting and has complied with the advance notice procedures set forth in our bylaws. Under our bylaws, in the event we call a special meeting of shareholders for the purpose of electing one or more trustees, a shareholder may nominate an individual or individuals (as the case may be) for election as a trustee if the shareholder provides timely notice, in writing, to our Secretary at our principal executive offices, containing the information and following the procedures required by the advance notice provisions in our bylaws, as described above for submitting nominations for consideration at an annual meeting of shareholders. To be timely, a shareholder's notice must be delivered not earlier than the 150th day prior to such special meeting and not later than 5:00 p.m. (Eastern Time) on the later of (1) the 120th day prior to such special meeting or (2) the 10th day following the day on which public announcement is first made of the date of the special meeting and of the nominees proposed by the trustees to be elected at such meeting. Neither the postponement or adjournment of a special meeting, nor the public announcement of such postponement or adjournment, shall commence a new time period for the giving of a shareholder's notice.

Meetings of Shareholders

        Under our bylaws, a meeting of our shareholders will be held at least annually at a date and time set by our board. Meetings of shareholders may be called only by a majority of our board.

Liability and Indemnification of Trustees and Officers

        To the maximum extent permitted by Maryland law, our declaration of trust includes provisions limiting the liability of our trustees and officers for money damages. Under our bylaws, we are required, to the maximum extent permitted by Maryland law, to indemnify (a) any present or former trustee or officer of our company who is made or threatened to be made a party to a proceeding by reason of his or her service in that capacity or (b) any individual who, while a trustee or officer of our company and, at our request, serves or has served as a trustee, director, officer or partner of another REIT, corporation, partnership, joint venture, trust, employee benefit plan or other enterprise and who is made or threatened to be made a party to a proceeding by reason of his or her service in that capacity and to pay or reimburse their reasonable expenses in advance of final disposition of the proceeding. Our bylaws also permit us to indemnify and advance expenses to any person who served any predecessor in the capacities described above and any present or former shareholder, employee or agent of us or any such predecessor. Except with respect to proceedings to enforce rights to indemnification, we are only required to indemnify our trustees and officers as described in this paragraph in connection with a proceeding initiated by any such person against us if such proceeding was authorized by our board.

        The Maryland REIT law permits a REIT to indemnify and advance expenses to its trustees, officers, employees and agents to the same extent permitted by the Maryland General Corporation Law, or MGCL, for directors and officers of Maryland corporations. The MGCL permits a corporation to indemnify its present and former directors and officers, among others, against judgments, penalties, fines, settlements and reasonable expenses actually incurred by them in connection with any proceeding to which they may be made, or threatened to be made, a party by reason of their service in those

25

capacities. However, a Maryland corporation is not permitted to provide this type of indemnification if the following is established:

•

the act or omission of the director or officer was material to the matter giving rise to the proceeding and (1) was committed in bad faith or (2) was the result of active and deliberate dishonesty;



•

the director or officer actually received an improper personal benefit in money, property or services; or



•

in the case of any criminal proceeding, the director or officer had reasonable cause to believe that the act or omission was unlawful.

        The MGCL permits a corporation to advance reasonable expenses to a director or officer upon the corporation's receipt of the following:

•

a written affirmation by the director or officer of his good faith belief that he has met the standard of conduct necessary for indemnification by the corporation; and



•

a written undertaking by him or on his behalf to repay the amount paid or reimbursed by the corporation if it is ultimately determined that this standard of conduct was not met.

        We have also entered into indemnification agreements with all of our trustees and certain of our officers providing for procedures for indemnification by us to the fullest extent permitted by law and advancements by us of certain expenses and costs relating to claims, suits or proceedings arising from their service to us.

        Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, trustees, officers or persons controlling us pursuant to the foregoing provisions of Maryland law and our declaration of trust and bylaws, we have been informed that in the opinion of the SEC such indemnification is against public policy as expressed in the Securities Act and therefore is unenforceable.

Shareholder Liability

        Under the Maryland REIT law, a shareholder is generally not personally liable for the obligations of a REIT solely as a result of his status as a shareholder. Our declaration of trust provides that no shareholder will be liable for any debt, claim, demand, judgment or obligation of any kind of us by reason of being a shareholder. Despite these facts, our legal counsel has advised us that in some jurisdictions the possibility exists that shareholders of a trust entity like us may be held liable for acts or obligations of the trust. While we intend to conduct our business in a manner designed to minimize potential shareholder liability, we can give no assurance that you can avoid liability in all instances in all jurisdictions. Our trustees have not provided in the past and do not intend to provide insurance covering these risks to our shareholders.

Indemnification by Our Shareholders and Arbitration of Claims

        Under our declaration of trust, each shareholder is liable to us for, and shall indemnify and hold harmless us and our affiliates from and against, all costs, expenses, penalties, fines or other amounts, including without limitation, reasonable attorneys' and other professional fees, whether third party or internal, arising from a shareholder's breach of or failure to fully comply with any covenant, condition or provision of our declaration of trust or bylaws (including the advance notice provisions of our bylaws) or any action by or against us in which the shareholder is not the prevailing party, and shall pay such amounts on demand, together with interest on such amounts, which interest will accrue at the lesser of 18% per annum and the maximum amount permitted by law, from the date such costs or other amounts are incurred until the receipt of payment.

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        Our declaration of trust provides that any action brought against us or any trustee, officer, manager (including RMR or its successor), agent or employee of us, by a shareholder, either on such shareholder's behalf, on behalf of us or on behalf of any series or class of shares or shareholders, including claims relating to the interpretation, effect, validity or enforcement of our declaration of trust or bylaws, derivative actions and class actions, shall, on the demand of any party to such dispute, be resolved through binding arbitration in accordance with the procedures set forth in our bylaws. Our bylaws require any such arbitration be conducted in accordance with the Commercial Arbitration Rules of the American Arbitration Association, except as modified in our bylaws and in accordance with our bylaws. With limited exceptions, each party is required to bear its own costs in the arbitration, and the arbitrators may not render an award that would include shifting of such costs or, in a derivative case, award any portion of our award to the claimant or the claimant's attorneys. Our declaration of trust and bylaws provide that the award of the arbitrators shall be final and binding on the parties and shall be the sole and exclusive remedy between the parties to the dispute relating to the dispute.

Transactions with Affiliates

        Our declaration of trust allows us to enter into contracts and transactions of any kind with any person, including any of our trustees, officers, employees or agents or any person affiliated with them. Other than general legal principles applicable to self dealing by trustees, interested trustee transactions and corporate opportunities, there are no prohibitions in our declaration of trust or bylaws which would prohibit dealings between us and our affiliates.

Voting by Shareholders

        Whenever shareholders are required or permitted to take any action by a vote, the action may only be taken by a vote at a shareholders meeting. Under our bylaws, shareholders do not have the right to take any action by written consent. With respect to matters brought before a meeting of shareholders other than the election of trustees, except where a different voting standard is required by any applicable law, the listing requirements of the principal exchange on which our common shares are listed or a specific provision of our declaration of trust, (a) if the matter is approved by at least 60% of the trustees then in office, including 60% of the independent trustees then in office, a majority of all the votes cast at the meeting shall be required to approve the matter and (b) if the matter is not approved by at least 60% of the trustees then in office, including 60% of the independent trustees then in office, 75% of all common shares entitled to vote at the meeting shall be required to approve the matter.

Restrictions on Ownership and Transfers of Common Shares

        Our declaration of trust restricts the amount of shares that shareholders may own. These restrictions are intended to assist with REIT compliance under the Code and otherwise to promote our orderly governance.

        Our declaration of trust provides that no person may own, or be deemed to own by virtue of the attribution provisions of the Code, more than 9.8% of the number or value (whichever is more restrictive) of shares of any class or series of our outstanding shares of beneficial interest, including our common shares. Our declaration of trust also prohibits any person from beneficially or constructively owning shares if that ownership would result in us being closely held under Section 856(h) of the Code or would otherwise cause us to fail to qualify as a REIT.

        Our board, in its discretion, may exempt other persons from this ownership limitation, so long as our board determines, among other things, that it is in our best interest. Our board may not grant an

27

exemption if the exemption would result in our failing to qualify as a REIT. In determining whether to grant an exemption, our board may consider, among other factors, the following:

•

the general reputation and moral character of the person requesting an exemption;



•

whether the person's ownership of shares would be direct or through ownership attribution;



•

whether the person's ownership of shares would interfere with the conduct of our business, including without limitation, our ability to acquire additional properties;



•

whether granting an exemption would adversely affect any of our existing contractual arrangements or business policies;



•

whether the person to whom the exemption would apply has been approved as an owner of us by all regulatory or other governmental authorities who have jurisdiction over us; and



•

whether the person to whom the exemption would apply is attempting to change control of us or affect our policies in a way which our board, in its discretion, considers adverse to our best interests or those of our shareholders.

        In addition, our board may require such rulings from the IRS, opinions of counsel, representations, undertakings or agreements it deems advisable in order to make the foregoing decisions.

        If a person attempts a transfer of our shares of beneficial interest in violation of the ownership limitations described above, then our board may deem that the number of shares which would cause the violation will be automatically transferred to a trust, or the Charitable Trust, for the exclusive benefit of one or more charitable beneficiaries designated by us. The prohibited owner will:

•

have no rights in the shares held in the Charitable Trust;



•

not benefit economically from ownership of any shares held in the Charitable Trust (except to the extent provided below upon sale of the shares);



•

have no rights to distributions;



•

not possess any rights to vote or other rights attributable to the shares held in the Charitable Trust; and



•

have no claim, cause of action or other recourse whatsoever against the purported transferor of such shares.

        Unless otherwise directed by our board, within 20 days of receiving notice from us that shares have been transferred to the Charitable Trust, or as soon thereafter as practicable, the trustee of the Charitable Trust will sell such shares (together with the right to receive distributions with respect to such shares) to a person, whose ownership of the shares will not violate the ownership limitations set forth in our declaration of trust. Upon such sale, the interest of the charitable beneficiary in the shares sold will terminate, and the trustee of the Charitable Trust will distribute the net proceeds of the sale to the prohibited owner and to the beneficiary of the Charitable Trust as follows:

        The prohibited owner will receive the lesser of:

(1)

the net price paid by the prohibited owner for the shares or, if the prohibited owner did not give value for the shares in connection with the event causing the shares to be held in the Charitable Trust, for example, a gift, devise or other similar transaction, the market price of the shares on the day of the event causing the shares to be transferred to the Charitable Trust, less the costs, expenses and compensation of the Charitable Trust and us; and



(2)

the net sales proceeds received by the trustee of the Charitable Trust from the sale of the shares held in the Charitable Trust.

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        Any net sale proceeds in excess of the amount payable to the prohibited owner shall be paid to the charitable beneficiary, less the costs, expenses and compensation of the Charitable Trust and us.

        If, prior to our discovery that shares of beneficial interest have been transferred to the Charitable Trust, a prohibited owner sells those shares, then:

(1)

those shares will be deemed to have been sold on behalf of the Charitable Trust; and



(2)

to the extent that the prohibited owner received an amount for those shares that exceeds the amount that the prohibited owner was entitled to receive from a sale by the trustee of the Charitable Trust, the prohibited owner must promptly pay the excess to the trustee of the Charitable Trust upon demand.

        Also, shares of beneficial interest held in the Charitable Trust will be deemed to have been offered for sale to us, or our designee, at a price per share equal to the lesser of:

(1)

the price per share in the transaction that resulted in the transfer to the Charitable Trust or, in the case of a devise or gift, the market price per such share on the day of the event causing the shares to become held by the Charitable Trust, less the costs, expenses and compensation of the Charitable Trustee, if any, and us; and



(2)

the market price per share on the date we, or our designee, accept the offer, less the costs, expenses and compensation of the Charitable Trustee, if any, and us.

        We will have the right to accept the offer until the trustee of the Charitable Trust has sold the shares held in the Charitable Trust. The net proceeds of the sale to us will be distributed similar to any other sale by a trustee of the Charitable Trust. Our board may retroactively amend, alter or repeal any rights which the Charitable Trust, the trustee of the Charitable Trust or the beneficiary of the Charitable Trust may have under our declaration of trust, except that our board may not retroactively amend, alter or repeal any obligations to pay amounts incurred prior to such time and owed or payable to the trustee of the Charitable Trust. The trustee of the Charitable Trust will be indemnified by us or from the proceeds from the sale of shares held in the Charitable Trust for its costs and expenses reasonably incurred in connection with conducting its duties and satisfying its obligations under our declaration of trust and is entitled to receive reasonable compensation for services provided.

        Costs, expenses and compensation payable to the Charitable Trustee may be funded from the Charitable Trust or by us. We will be entitled to reimbursement on a first priority basis (after payment in full of amounts payable to the Charitable Trustee) from the Charitable Trust for any such amounts funded by us.

        In addition, costs and expenses incurred by us in the process of enforcing the ownership limitations set forth in our declaration of trust, in addition to reimbursement of costs, expenses and compensation of the trustee of the Charitable Trust which have been funded by us, may be collected from the Charitable Trust.

        The restrictions described above will not preclude the settlement of any transaction entered into through the facilities of any national securities exchange or automated inter-dealer quotation system. Our declaration of trust provides, however, that the fact that the settlement of any transaction occurs will not negate the effect of any of the foregoing limitations and any transferee in such a transaction will be subject to all of the provisions and limitations described above.

        Every owner of 5% or more of any class or series of our shares is required to give written notice to us within 30 days after the end of each taxable year, and also within three business days after a request from us, stating the name and address of the owner, the number of shares of each class and series of our shares which the owner beneficially owns, and a description of the manner in which those shares are held. If the Code or applicable tax regulations specify a threshold below 5%, this notice

29

provision will apply to those persons who own our shares of beneficial interest at the lower percentage. In addition, each shareholder is required to provide us upon demand with any additional information that we may request in order to determine our status as a REIT, to comply or determine our compliance with the requirements of any taxing authority or other government authority and to determine and ensure compliance with the foregoing ownership limitations.

Compliance With Governing Documents and Applicable Law

        Our declaration of trust creates a covenant between us and our shareholders which requires our shareholders (1) to comply with our declaration of trust and our bylaws and (2) to comply, and assist us in complying, with all applicable requirements of federal and state laws, and our contractual obligations which arise by reason of the shareholder's ownership interest in us, and with all other laws or agreements which apply to us or our businesses, assets or operations and which require action or inaction on the part of such shareholder.

Business Combinations

        The MGCL contains a provision which regulates business combinations with interested shareholders. This provision applies to Maryland REITs. Under the MGCL, business combinations such as mergers, consolidations, share exchanges, or, in circumstances specified in the statute, an asset transfer or issuance or reclassification of equity securities between a Maryland REIT and an interested shareholder or an affiliate of an interested shareholder are prohibited for five years after the most recent date on which the interested shareholder becomes an interested shareholder. Under the MGCL the following persons are deemed to be interested shareholders:

•

any person who beneficially owns 10% or more of the voting power of the trust's outstanding voting shares; or



•

an affiliate or associate of the trust who, at any time within the two year period prior to the date in question, was the beneficial owner of 10% or more of the voting power of the then outstanding voting shares of the trust.

        After the five year prohibition period has ended, a business combination between a trust and an interested shareholder generally must be recommended by our board and must receive the following shareholder approvals:

•

the affirmative vote of at least 80% of the votes entitled to be cast; and



•

the affirmative vote of at least two thirds of the votes entitled to be cast by holders of voting shares other than shares held by the interested shareholder with whom or with whose affiliate the business combination is to be effected or held by an affiliate or associate of the interested shareholder.

        The supermajority vote requirements do not apply if shareholders receive the minimum price set forth in the MGCL for their shares and the consideration is received in cash or in the same form as previously paid by the interested shareholder for its shares.

        The foregoing provisions of the MGCL do not apply, however, to business combinations that are approved or exempted by our board prior to the time that the interested shareholder becomes an interested shareholder. Our board has adopted a resolution that any business combination between us and any other person is exempted from the provisions of the MGCL described in the preceding paragraphs, provided that the business combination is first approved by the board of trustees, including the approval of a majority of the members of the board of trustees who are not affiliates or associates of the interested shareholder. This resolution, however, may be altered or repealed in whole or in part at any time.

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Control Share Acquisitions

        The MGCL contains a provision which regulates control share acquisitions. This provision also applies to Maryland REITs. The MGCL provides that control shares of a Maryland REIT acquired in a control share acquisition have no voting rights except to the extent that the acquisition is approved by a vote of two thirds of the votes entitled to be cast on the matter, excluding shares of beneficial interest owned by the acquiror, by officers or by trustees who are employees of the trust. Control shares are voting shares of beneficial interest which, if aggregated with all other shares of beneficial interest previously acquired by the acquiror, or in respect of which the acquiror is able to exercise or direct the exercise of voting power (except solely by virtue of a revocable proxy), would entitle the acquiror to exercise voting power in electing trustees within one of the following ranges of voting power:

•

one tenth or more but less than one third;



•

one third or more but less than a majority; or



•

a majority or more of all voting power.

        An acquiror must obtain the necessary shareholder approval each time it acquires control shares in an amount sufficient to cross one of the thresholds noted above.

        Control shares do not include shares which the acquiring person is entitled to vote as a result of having previously obtained shareholder approval. The MGCL provides a list of exceptions from the definition of control share acquisition.

        A person who has made or proposes to make a control share acquisition, upon satisfaction of the conditions set forth in the statute, including an undertaking to pay expenses, may compel the board of trustees of the trust to call a special meeting of shareholders to be held within 50 days of demand to consider the voting rights of the shares. If no request for a meeting is made, the trust may itself present the matter at any shareholders meeting.

        If voting rights are not approved at the meeting or if the acquiring person does not deliver an acquiring person statement as required by the statute, then the trust may redeem any or all of the control shares for fair value determined as of the date of the last control share acquisition by the acquiror or of any meeting of shareholders at which the voting rights of those shares are considered and not approved. The right of the trust to redeem any or all of the control shares is subject to conditions and limitations listed in the statute.

        The trust may not redeem shares for which voting rights have previously been approved. Fair value is determined without regard to the absence of voting rights for the control shares. If 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, all other shareholders may exercise appraisal rights. The fair value of the shares as determined for purposes of these appraisal rights may not be less than the highest price per share paid by the acquiror in the control share acquisition.

        The control share acquisition statute does not apply to the following:

•

shares acquired in a merger, consolidation or share exchange if the trust is a party to the transaction; or



•

acquisitions approved or exempted by a provision in the declaration of trust or bylaws of the trust adopted before the acquisition of shares.

        Our bylaws contain a provision exempting any and all acquisitions by any person of our common shares from the control share acquisition statute. This provision may be amended or eliminated at any time in the future.

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Amendment to Our Declaration of Trust, Dissolution and Mergers

        Under the Maryland REIT law, a REIT generally cannot dissolve, amend its declaration of trust or merge, unless these actions are approved by the affirmative vote of shareholders holding at least two thirds of all shares entitled to be cast on the matter. The statute allows a trust's declaration of trust to set a lower percentage, so long as the percentage is not less than a majority of all the votes entitled to be cast on the matter. Our declaration of trust provides for approval of any of the foregoing actions by a majority of all votes entitled to be cast on these actions provided the action in question has been approved by 60% of our board, including 60% of our Independent Trustees. Our declaration of trust further provides that if permitted in the future by Maryland law, the majority required to approve any of the foregoing actions which have been approved by 60% of our board, including 60% of our Independent Trustees, will be the affirmative vote of a majority of the votes cast on the matter. Under the Maryland REIT law, a declaration of trust may permit the trustees by a two thirds vote to amend the declaration of trust from time to time to qualify as a REIT under the Code or the Maryland REIT law without the affirmative vote or written consent of the shareholders. Our declaration of trust permits this type of action by our board. Our declaration of trust also permits our board to increase or decrease the aggregate number of shares that we may issue and to effect changes in our unissued shares, as described more fully under "—Description of Shares of Beneficial Interest," and to change our name or the name of any class or series of our shares, in each case without shareholder approval, and provides that, to the extent permitted in the future by Maryland law, our board may amend any other provision of our declaration of trust without shareholder approval.

Anti-Takeover Effect of Our Declaration of Trust and Bylaws

        The following provisions in our declaration of trust and bylaws and in Maryland law could delay or prevent a change in our control:

•

the limitation on transfer and ownership of more than 9.8% of the number or value of shares of any class or series of our outstanding shares of beneficial interest, including our common shares;



•

the classification of our board into classes and the election of each class for three-year staggered terms;



•

the requirement of the affirmative vote of at least 75% of the outstanding shares of beneficial interest entitled to be cast in the election of trustees for removal of our trustees;



•

the fact that the number of our trustees may be fixed only by vote of our board, that a vacancy on our board may be filled only by the affirmative vote of a majority of our remaining trustees and that our shareholders are not entitled to act without a meeting;



•

the provision that only our board may call meetings of shareholders;



•

the advance notice requirements for shareholder nominations for trustees and other proposals; and



•

the power of our board to authorize and to cause us to issue additional shares of beneficial interest, including additional classes of shares of beneficial interest with rights defined at the time of issuance, without shareholder approval.

PLAN OF DISTRIBUTION

        We may sell the offered securities (a) through underwriters or dealers, (b) directly to purchasers, including our affiliates, (c) through agents or (d) through a combination of any of these methods. The prospectus supplement will include the following information:

•

the terms of the offering;

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•

the names of any underwriters or agents;



•

the name or names of any managing underwriter or underwriters;



•

the purchase price of the securities;



•

the net proceeds from the sale of the securities;



•

any delayed delivery arrangements;



•

any underwriting discounts, commissions and other items constituting underwriters' compensation;



•

any initial public offering price;



•

any discounts or concessions allowed or reallowed or paid to dealers; and



•

any commissions paid to agents.

        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 the market prices, or at negotiated prices.

        In compliance with Financial Regulatory Authority, or FINRA, guidelines, the maximum commission or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus or any applicable prospectus supplement.

        If underwriters are used in the sale, the underwriters will acquire the securities for their own account. The underwriters may resell the securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless we inform you otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions, and the underwriters will be obligated to purchase all the offered securities if they purchase any of them. The underwriters may change from time to time any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers.

        In order to facilitate the offering of securities, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. Specifically, the underwriters may over-allot in connection with the offering, creating a short position in the securities for their account. In addition, to cover over-allotments or to stabilize the price of the shares, the underwriters may bid for, and purchase, shares in the open market. Finally, an underwriting syndicate may reclaim selling concessions allowed to an underwriter or a dealer for distributing the securities in the offering if the syndicate repurchases previously distributed shares in transactions to cover syndicate short positions, in stabilization transactions, or otherwise. Any of these activities may stabilize or maintain the market price of the offered securities above independent market levels. The underwriters are not required to engage in these activities and may end any of these activities at any time.

        Some or all of the securities that we offer through this prospectus may be new issues of securities with no established trading market. Any underwriters to whom we sell securities for public offering and sale may make a market in those securities, but they will not be obligated to and they may discontinue any market making at any time without notice. Accordingly, we cannot assure you of the liquidity of, or continued trading markets for, any securities offered pursuant to this prospectus.

        If dealers are used in the sale of securities, we will sell the securities to them as principals. They may then resell those securities to the public at varying prices determined by the dealers at the time of

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resale. We will include in the prospectus supplement the names of the dealers and the terms of the transaction.

        We may sell the securities directly. In this case, no underwriters or agents would be involved. We may also sell the securities through agents designated from time to time. In the prospectus supplement, we will name any agent involved in the offer or sale of the offered securities, and we will describe any commissions payable to the agent. Unless we inform you otherwise in the prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

        We may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities. We will describe the terms of any such sales in the prospectus supplement.

        If we so indicate in the prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase securities at the public offering price under delayed delivery contracts. These contracts would provide for payment and delivery on a specified date in the future. The contracts would be subject only to those conditions described in the prospectus supplement. The prospectus supplement will describe the commission payable for solicitation of those contracts.

        We may have agreements with the agents, dealers and underwriters to indemnify them against specified liabilities, including liabilities under the federal securities laws or to contribute to the payments that the agents, dealers or underwriters may be required to make in respect of those liabilities. Indemnification may include each person who is an affiliate of or controls one of these specified indemnified persons within the meaning of the federal securities laws or is required to contribute to payments that the agents, dealers or underwriters may be required to make in respect of those liabilities. Agents, dealers and underwriters may be customers of, engage in transactions with or perform services for us in the ordinary course of their businesses.

        Each underwriter, dealer and agent participating in the distribution of any of the securities that are issuable in bearer form will agree that it will not offer, sell or deliver, directly or indirectly, securities in bearer form in the United States or to United States persons, other than qualifying financial institutions, during the restricted period, as defined in United States Treasury Regulations Section 1.163-5(c)(2)(i)(D)(7).

VALIDITY OF THE OFFERED SECURITIES

        Sullivan & Worcester LLP, as to certain matters of New York law, and Venable LLP, as to certain matters of Maryland law, will pass upon the validity of the offered securities for us. Sullivan & Worcester LLP also represents RMR, our manager, and certain of its affiliates on various matters.

EXPERTS

        Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements and schedule included in our Annual Report on Form 10-K for the year ended December 31, 2009, and the Statements of Revenues and Certain Operating Expenses for each of 75 Pleasant Street and the CWH Government Buildings, as set forth in their reports, which are incorporated by reference in this prospectus and elsewhere in the registration statement. Our financial statements and schedule are incorporated by reference in reliance on Ernst & Young LLP's reports, given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

        We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy any reports, statements or other information on file at the SEC's public

34

reference room at 100 F Street, N.E., Washington, D.C. 20549. You can request copies of those documents upon payment of a duplicating fee to the SEC. This prospectus is part of a registration statement and does not contain all of the information set forth in the registration statement. You may call the SEC at 1-800-SEC-0330 for further information on the operation of the public reference rooms. You can review our SEC filings and the registration statement by accessing the SEC's Internet site at www.sec.gov. Website addresses are included in this prospectus as textual references only and the information in such websites is not incorporated by reference into this prospectus or related registration statement.

        Our common shares are traded on the NYSE under the symbol "GOV," and you can review similar information concerning us at the office of the NYSE at 20 Broad Street, New York, New York 10005.

DOCUMENTS INCORPORATED 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. Statements in this prospectus regarding the contents of any contract or other document may not be complete. You should refer to the copy of the contract or other document filed as an exhibit to the registration statement. Later information filed with the SEC will update and supersede information we have included or incorporated by reference in this prospectus.

        We incorporate by reference the documents listed below and any filings made after the date of the initial filing of the registration statement of which this prospectus is a part made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act until the offering of the securities made by this prospectus is completed or terminated:

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2009, filed on February 22, 2010;



•

our Quarterly Report on Form 10-Q for fiscal quarter ended March 31, 2010, filed on May 5, 2010;



•

our Current Reports on Form 8-K dated March 25, 2010, May 13, 2010, June 18, 2010 and July 2, 2010, and our Current Report on Form 8-K/A dated July 2, 2010;



•

the information identified as incorporated by reference under Items 10, 11, 12, 13 and 14 of Part III of our Annual Report on Form 10-K for the fiscal year ended December 31, 2009, from our definitive Proxy Statement for our Annual Meeting of Shareholders, filed on February 22, 2010; and



•

the description of our common shares contained in our registration statement on Form 8-A dated May 20, 2009, and including all amendments and reports filed for the purpose of updating such description.

        We will provide you with a copy of the information we have incorporated by reference, excluding exhibits other than those which we specifically incorporate by reference in this prospectus. You may obtain this information at no cost by writing or telephoning us at: 400 Centre Street, Newton, Massachusetts 02458, (617) 219-1440, Attention: Investor Relations.

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STATEMENT CONCERNING LIMITED LIABILITY

        THE AMENDED AND RESTATED DECLARATION OF TRUST ESTABLISHING GOVERNMENT PROPERTIES INCOME TRUST, DATED JUNE 8, 2009, AS AMENDED, AS FILED WITH THE STATE DEPARTMENT OF ASSESSMENTS AND TAXATION OF MARYLAND, PROVIDES THAT NO TRUSTEE, OFFICER, SHAREHOLDER, EMPLOYEE OR AGENT OF GOVERNMENT PROPERTIES INCOME TRUST SHALL BE HELD TO ANY PERSONAL LIABILITY, JOINTLY OR SEVERALLY, FOR ANY OBLIGATION OF, OR CLAIM AGAINST, GOVERNMENT PROPERTIES INCOME TRUST. ALL PERSONS DEALING WITH GOVERNMENT PROPERTIES INCOME TRUST IN ANY WAY SHALL LOOK ONLY TO THE ASSETS OF GOVERNMENT PROPERTIES INCOME TRUST FOR THE PAYMENT OF ANY SUM OR THE PERFORMANCE OF ANY OBLIGATION.

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Table of Contents

7,000,000 Shares

Government Properties Income Trust

Common Shares of Beneficial Interest

PROSPECTUS SUPPLEMENT

MORGAN STANLEY
RBC CAPITAL MARKETS
WELLS FARGO SECURITIES
CITI
JEFFERIES & COMPANY
MORGAN KEEGAN & COMPANY, INC.
UBS INVESTMENT BANK

August                         , 2010