PROSPECTUS SUPPLEMENT SUMMARY

The Company

          AvalonBay Communities, Inc. is a real estate investment trust, or REIT, and S&P 500 Index company that owns one of the largest portfolios of high-quality multifamily communities in the United States. We are focused on the development, redevelopment, acquisition, operation and management of apartment communities in high barrier-to-entry markets in the Northeast, Mid-Atlantic and West Coast regions of the United States.

          At September 30, 2012, we owned or held a direct or indirect ownership interest in:

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183 operating apartment communities containing 53,487 apartment homes in nine states and the District of Columbia, of which seven communities containing 1,802 apartment homes were under reconstruction;



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22 communities under construction that are expected to contain an aggregate of 6,614 apartment homes when completed; and



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land or rights to land in which we expect to develop an additional 31 communities that, if developed as expected, will contain an estimated 8,837 apartment homes.

          Our principal financial goal is to increase long-term shareholder value through our integrated multifamily investment and operating platform by pursuing a strategy of being leaders in market research and capital allocation and delivering a range of multifamily offerings tailored to serve the needs of the most attractive customer segments in the best-performing submarkets of the U.S. We pursue this strategy through three brand offerings, each targeting a different customer segment and price point. Our "Avalon" brand, our core offering, focuses on upscale apartment living and high-end amenities and services in urban and suburban markets. Our "AVA" brand is designed for people who want to live in or near urban neighborhoods and in close proximity to public transportation, services, shopping and night-life. AVA apartments are generally smaller, with many engineered for roommate living, featuring modern design and a technology focus. Our "Eaves by Avalon" brand is designed for renters who seek quality apartment living, often in a suburban setting, with practical amenities and services at a more modest price point.

          AvalonBay elected to qualify as a REIT for federal income tax purposes for the taxable year ended December 31, 1994, and has not terminated or revoked such election. As a REIT, with limited exceptions, we will not be taxed under federal and certain state income tax laws at the corporate level on our net income to the extent net income is distributed to our stockholders. We have historically made sufficient distributions to avoid tax on retained income, and we intend to make sufficient distributions to avoid income tax at the corporate level. While we believe that we are organized and qualified as a REIT and we intend to operate in a manner that will allow us to continue to qualify as a REIT, there can be no assurance that we will be successful in this regard. Qualification as a REIT involves the application of highly technical and complex provisions of the Internal Revenue Code of 1986, as amended, or the Code, for which there are limited judicial and administrative interpretations and involves the determination of a variety of factual matters and circumstances not entirely within our control.

          Our principal executive offices are located at Ballston Tower, 671 N. Glebe Road, Suite 800, Arlington, Virginia 22203, Attention: Chief Financial Officer. Our telephone number is 703-329-6300. Our website is located at www.avalonbay.com. Information on our website is not deemed to be a part of this prospectus supplement or the attached prospectus.

Recent Developments

The Archstone Portfolio Acquisition

          On November 26, 2012, we entered into an asset purchase agreement, or the Purchase Agreement, with (i) Equity Residential and its operating partnership, ERP Operating Partnership LP, or, collectively, Equity Residential, (ii) Lehman Brothers Holdings Inc., or Lehman, and (iii) Archstone Enterprise LP, or Archstone, pursuant to which we and Equity Residential will acquire, directly or indirectly, all of the assets and entities owned by, and all of the liabilities of, Archstone (other than certain excluded liabilities).

          Pursuant to the Purchase Agreement and separate arrangements between us and Equity Residential governing the allocation of liabilities to be assumed under the Purchase Agreement, our portion of consideration under the Purchase Agreement is approximately $6.9 billion, and consists of the following:

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the issuance of 14,889,706 shares of our common stock to Archstone, valued at $1.9 billion, using the closing price for our common stock on the New York Stock Exchange on November 23, 2012 of $128.54;



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$669.0 million in cash;



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the assumption of indebtedness with a fair value of approximately $4.1 billion, consisting of $3.7 billion principal amount for consolidated borrowings, $238.3 million principal amount for our proportionate share of debt related to unconsolidated joint ventures, and $197.5 million representing the amount by which the fair value of the aforementioned debt exceeds the principal face value;



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an obligation to pay, when presented for redemption from time to time, approximately $132.2 million in respect of the liquidation value of and accrued dividends on outstanding Archstone preferred units; and



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the assumption of 40% of all other liabilities, known or unknown, of Archstone, other than certain excluded liabilities.

          For this consideration, we will acquire a portfolio of direct and indirect interests in apartment communities and net other liabilities that we refer to as the Archstone Portfolio Acquisition. The net proceeds of this offering will be used by us to fund the Archstone Portfolio Acquisition (including the fees and costs related thereto), repay a portion of the debt assumed in the Archstone Portfolio Acquisition, and help us preserve our financial flexibility.

          The Archstone Portfolio Acquistion represents a rare opportunity for us to buy a large portfolio of high-quality apartment communities that is concentrated in our existing high barrier-to-entry markets and is consistent with our strategic objective of more deeply penetrating our chosen markets with a broader range of products and services. For the nine months ended September 30, 2012, 98% of the net operating income, or NOI, from the consolidated apartment communities we expect to acquire in the Archstone Portfolio Acquisition is generated in our existing markets.

          The Archstone Portfolio Acquisition consists of the following:

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66 consolidated apartment communities, containing 22,222 apartment homes, of which six communities are under construction and are expected to contain 1,666 apartment homes upon completion;



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three parcels of land, which are consolidated and if developed as expected will contain a total of 968 apartment homes;

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interests in unconsolidated joint ventures in which we expect to be the general partner or managing member, which own 10 apartment communities containing 2,040 apartment homes, of which one community is under construction and is expected to contain 157 apartment homes upon completion; and



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a 40% ownership interest in unconsolidated joint venture arrangements with Equity Residential which will hold assets that we will jointly manage, sell to third parties, and/or subsequently transfer to Equity Residential or to us.

          The following table provides the approximate allocation of AvalonBay's investment in the Archstone Portfolio Acquisition:

          Under the Purchase Agreement, we will acquire 40% of the assets and liabilities of Archstone and Equity Residential will acquire the remaining 60% of the assets and liabilities of Archstone. We refer herein to 40% and 60% as our respective pro rata shares. We and Equity Residential are jointly and severally liable for most obligations to Lehman under the Purchase Agreement. The Purchase Agreement provides that the closing of the acquisitions thereunder must occur within 120 days after execution of the Purchase Agreement. If we and Equity Residential fail to close the acquisition, then Equity Residential and we could be liable for payment of a termination fee of $800.0 million (or $650.0 million if the Purchase Agreement is terminated in the first 60 days after signing) as discussed under "Purchase Agreement and Related Arrangements." The Archstone Portfolio Acquisition is also subject to customary closing conditions, which do not include our and Equity Residential's ability to obtain the necessary financing or lender consents for the transaction. Neither we nor Equity Residential could terminate the Purchase Agreement because of a lack of financing or lender consents without incurring the termination fee.

The Archstone Portfolio

          We believe the Archstone Portfolio Acquisition will create strategic, portfolio and financial benefits for us, including the following:

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It will increase our ownership of high-quality apartment communities in our existing markets.



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It will allow us to more closely align our portfolio allocation with our long-term geographic allocation goals.



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It will expand our portfolio into complementary submarkets with more varied product offerings.



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It will enable us to more rapidly implement our multi-branding strategy.



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It will provide enhanced corporate efficiencies due to our increased scale.

          High-Quality Portfolio Concentrated in Our Markets.    The following table provides the percentage of NOI generated during the nine months ended September 30, 2012, by region for our consolidated apartment communities, as well as communities that were under construction, or for which substantial redevelopment is planned or that occurred during 2012, pro forma for the Archstone Portfolio Acquisition (dollars in thousands):

          For the nine months ended September 30, 2012, pro forma for the Archstone Portfolio Acquisition, 99% of the NOI from our apartment communities would be concentrated in our existing high barrier-to-entry markets.

          In connection with the Archstone Portfolio Acquisition, we will acquire interests in certain non-core assets or communities in non-core markets for us, including interests in assets in Texas, Florida and Germany. Some of these interests will be held and managed in a joint venture with Equity Residential, pending disposition or assignment to Equity Residential or us.

          Achieving Geographic Portfolio Allocation Goals.    We believe that the Archstone Portfolio Acquisition will allow us to bring our overall portfolio more closely in line with our long-term goals for regional allocation. In particular, our current Southern California portfolio is expected to grow from approximately 10,400 apartment homes at September 30, 2012 to approximately 19,200 apartment homes pro forma for the Archstone Portfolio Acquisition. Other geographic allocation adjustments expected to be achieved through the Archstone Portfolio Acquisition include a reduction in our relative concentration in the New England and Metro New York/New Jersey regions (where relatively few of the Archstone Portfolio Acquisition apartment communities to be acquired by us are located) and an increase in our Mid-Atlantic region presence.

          Complementary Submarket and Product Positioning.    Many of the apartment communities to be acquired by us in the Archstone Portfolio Acquisition are located in submarkets that are different than, but complementary to, the submarkets where our current apartment communities are located

within each of our six main market regions. For example, in the Mid-Atlantic region, our existing apartment communities are more concentrated in suburban locations such as the Rockville/Gaithersburg corridor in suburban Maryland and the Tysons Corner and Fairfax submarkets in Northern Virginia. By contrast, the Archstone Portfolio Acquisition apartment communities in the Washington, D.C. market are concentrated in more urban, higher density submarkets such as the Rosslyn/Ballston corridor in Arlington, Virginia and the Wisconsin/Connecticut Avenue NW corridor in Washington D.C. We believe that many of the apartment communities to be acquired by us in the Archstone Portfolio Acquisition are also positioned to appeal to a somewhat different consumer segment than our existing assets based on the different characteristics of the Archstone Portfolio Acquisition apartment communities, which are generally more heavily weighted towards smaller apartments in high-rise buildings. We believe the Archstone Portfolio Acquisition will provide us with a more diversified portfolio with broader product offerings within each region where we currently do business.

          Increased Scale Supports our Multi-Brand Strategy.    We recently introduced a three brand strategy. We are currently in the process of rolling out our two new brands (AVA and Eaves by Avalon) at certain of our existing apartment communities and refining our core Avalon brand. We believe that the Archstone Portfolio Acquisition will allow us to extend our three brand platform across additional assets in an efficient manner, bringing these brands to a meaningful market presence sooner than we otherwise would be able to do so.

          Enhanced Corporate Efficiencies Due to Increased Scale.    We expect that the increased scale of our apartment community portfolio from the Archstone Portfolio Acquisition will require a lower proportionate increase in our corporate and property management overhead and general and administrative expenses. We believe that our corporate support functions, including our customer care center in Virginia Beach and our marketing, customer insight, and market research groups in our corporate headquarters in Arlington, Virginia, are positioned to allow for absorption of additional assets to provide additional operating leverage.

          The table below provides details by region for the operating apartment communities as of September 30, 2012 in which we expect to acquire a direct or indirect interest in connection with the Archstone Portfolio Acquisition.

          The table below provides certain details with respect to properties under construction or planned for development in which we expect to acquire a direct or indirect interest in connection with the Archstone Portfolio Acquisition. In addition, Archstone controls certain other land parcels primarily through purchase options. Some of these option contracts may be assigned to us at closing in addition to the assets listed below.

Adjustments to the Anticipated Archstone Portfolio Acquisition

          The properties that will be part of the overall transaction involving Archstone and the assets and liabilities to be held by certain joint ventures we expect to form with Equity Residential are subject to final adjustment at closing between us and Equity Residential pursuant to arrangements separate from the Purchase Agreement. These arrangements are designed to account for ongoing changes in the status of the assets and liabilities up until closing. For example, some of the properties and other assets may be sold and liabilities may be settled before closing. As a result, the final allocation between us and Equity Residential of the properties, other assets and liabilities in connection with the the overall transaction involving Archstone could change and impact the amount of consideration to be paid by us under the Purchase Agreement.

Assumed Indebtedness

          We will assume approximately $3.7 billion principal amount of consolidated indebtedness in connection with the Archstone Portfolio Acquisition. Of this amount, Fannie Mae and Freddie Mac (the Government Sponsored Enterprises or GSEs) are the lenders in connection with approximately (i) $2.8 billion of pooled debt, (ii) $463.4 million of tax-exempt bond financing for which the GSEs provide credit enhancement and liquidity and (iii) $104.4 million of other single asset loans (collectively, the GSE Indebtedness). We have entered into a commitment letter with each of Fannie Mae and Freddie Mac whereby they have provided us with their consents to the transaction contemplated by the Purchase Agreement and our and Equity Residential's assumption of the allocable portions of the loans made to Archstone. In connection with such consents, we have agreed to repay approximately $200.0 million of the GSE Indebtedness owed to Fannie Mae at the closing of the Archstone Portfolio Acquisition. In addition, with the net proceeds of this offering, we also intend to repay $753.0 million of GSE Indebtedness and other assumed indebtedness, bringing the total amount of assumed indebtedness that we expect to repay at the closing of the Archstone Portfolio Acquisition to $953.0 million. The following table sets forth the consolidated indebtedness we will assume as of September 30, 2012, and on a pro forma basis giving effect to the repayment of indebtedness as discussed above.

Financial Highlights and Outlook

          Operating Results and Outlook.    Between January 1, 2012, and September 30, 2012, our portfolio of established communities achieved an increase in NOI of 8.1% compared to the same period of 2011. Throughout 2012, apartment fundamentals have remained strong, driven by a combination of a decline in the homeownership rate, modest employment growth and limited supply of new multifamily rental product. For the nine months ended September 30, 2012, our established apartment communities achieved an increase in rental revenue of 6.0% as compared to the prior year period, primarily from an increase of 5.8% in average rental rates and a 0.2% improvement in economic occupancy, as we have historically defined that term. On October 24, 2012 we updated our guidance for full year 2012 earnings per share — diluted, or EPS, to be in the range of $4.47 and $4.52, and Funds from Operations — diluted, or FFO, to be in the range of $5.45 to $5.50. FFO is a non-GAAP financial measure. For a description of how we define FFO and a reconciliation of FFO to net income, please see "Reconciliation of Non-GAAP Financial Measures" beginning on page F-18 of this prospectus supplement.

          On November 12, 2012, we issued a press release regarding the financial impact of Hurricane Sandy to us, in which we estimated the out-of-pocket costs to repair damages to be in the range of $5.0 to $7.0 million after considering insurance reimbursements. We now estimate that the aggregate out-of-pocket costs to repair damages associated with Hurricane Sandy will be in the range of $3.5 to $5.0 million, after considering insurance reimbursements. A portion of these out-of-pocket costs will

be capitalized, such that we expect the impact of these costs on reported earnings to be between $1.0 and $1.5 million, with the majority of the costs expected to be incurred during the fourth quarter of 2012.

          Current Operating Environment.    We anticipate market fundamentals impacting our business to remain favorable for the remainder of 2012 and into 2013. Our expectations are based in part on our outlook for employment conditions, where we anticipate moderate but accelerated job and population growth, particularly in the age groups that have historically demonstrated a higher propensity to rent. Our assessment of our portfolio's potential performance for 2013 also considers the individual demand/supply characteristics of each submarket in which we operate. Over the past several years supply within the majority of our markets has been below long-term trend levels, although it is expected to increase closer to long-term levels over the next several years. We anticipate that the properties we expect to acquire as part of the Archstone Portfolio Acquisition will show operating trends in line with our established communities.

          Acquisition Capitalization Rate.    As part of our due diligence process, we analyzed the anticipated capitalization rate we expect to derive from the Archstone Portfolio Acquisition. We define capitalization rate as NOI as a percentage of the purchase price after making adjustments to historical NOI to reflect anticipated growth in rental rates, as well as reserves for capital expenditures, property management fees, and other market conventions to estimate future stabilized NOI. We believe that the weighted average capitalization rate for the combined Archstone portfolio, including properties to be acquired both by us and by Equity Residential, is in the high 4% range. Our definition of NOI and calculation of the capitalization rate may not be comparable with those of other REITs because of differences in accounting policies, forward adjustments to historical NOI, assumed property management fees, reserves and other items. We also caution you not to place undue reliance on our estimates of NOI to be generated by the apartment communities we expect to acquire as part of the Archstone Portfolio Acquisition, because such estimates are based principally on data made available to us in the acquisition diligence process, combined with our experience in operating our own comparable apartment communities. Actual results could differ materially from expectations, as discussed in "Risk Factors," "Forward-Looking Statements" and other sections of this prospectus supplement, as well as our Form 10-K for the year ended December 31, 2011, as updated by subsequent filings with the SEC.

          Pro Forma Impact of the Archstone Portfolio Acquisition.    The following table presents our EPS and FFO per share for the year ended December 31, 2011 and the nine months ended September 30, 2012, on a historical basis and pro forma for the Archstone Portfolio Acquisition:

          The pro forma adjustments assume that the Archstone Portfolio Acquisition occurred on January 1, 2011, and reflect management's estimates of costs that would have been incurred during the respective periods for property management and additional general and administrative expenses for the Archstone Portfolio Acquisition. Assuming that the Archstone Portfolio Acquisition closed on January 1, 2011, and excluding one-time transaction costs, the transaction would have been approximately 7% accretive to our FFO per share for the nine months ended September 30, 2012. The actual impact of the Archstone Portfolio Acquisition in future periods will be affected by the timing of the transaction's closing, as well as the amount and timing of one-time transaction costs. We currently anticipate that we will incur $153.8 million in expensed transaction costs related to the

Archstone Portfolio Acquisition. We caution you not to place undue reliance on pro forma performance metrics because the contribution to EPS and FFO per share from the apartment communities we expect to acquire as part of the Archstone Portfolio Acquisition will depend on a number of factors that we cannot predict with certainty. Our actual experience operating the apartment communities we expect to acquire as part of the Archstone Portfolio Acquisition, following the closing of the transaction, including rental rates, economic occupancy, operating and capital expenditures and other items, may change our expectations with respect to the impact of the transaction on our EPS and FFO per share.

          Dividend Outlook.    Based on our estimates for our existing apartment communities and our expectations for apartment communities we anticipate acquiring as part of the Archstone Portfolio Acquisition, we expect to increase our common stock dividend for the first quarter of 2013 by a range of between 8% and 12% as compared to the dividend we previously declared and announced for the fourth quarter of 2012. This increase is supported by our current operating platform and recent operating trends, the expectation for continued favorable apartment fundamentals in 2013, and the contribution from apartment communities we expect to acquire as part of the Archstone Portfolio Acquisition. The payment of any dividend, however, is subject to the approval of our board of directors and there can be no assurance that economic conditions generally and/or their impact on our operating results and payout ratio will not lead us to change our expectation.

Purchase Agreement and Related Arrangements

          Pursuant to the Purchase Agreement, the acquisition is subject to customary closing conditions, including, among other things, the accuracy of the other parties' representations and warranties and compliance with covenants, subject in each case to significant materiality standards as well as the absence of a material adverse change with respect to the business, financial condition or results of operations of Archstone. There can be no assurance that any condition to the closing of the transaction will be satisfied or waived, if permitted, or that there will not be events, developments or changes that can cause the closing not to occur. Therefore, there can be no assurance with respect to the timing of the closing of the Archstone Portfolio Acquisition or whether the transaction will be completed on the currently contemplated terms, other terms or at all. There is no closing condition, relating to our or Equity Residential's ability to obtain the necessary financing or lender consents for the transaction. If we extend the closing beyond the 90th day following the execution of the Purchase Agreement, the purchase price will increase by an amount equal to $1.0 million per day thereafter. The amount of this increase would be paid 60% by Equity Residential and 40% by us, with each party's additional payment reduced by the amount of any accrued but unpaid dividends on the stock consideration payable by that party for the period prior to closing. The Purchase Agreement also provides that we, Equity Residential or Lehman may terminate the Purchase Agreement if the closing has not occurred by the 120^th day following the execution of the Purchase Agreement, so long as the failure of the closing to occur on or before this date was not due to a breach by the terminating party of its respective obligations under the Purchase Agreement and, in the case of us and Equity Residential, we pay the termination fee discussed below if, at the time, all of the conditions to closing are satisfied.

          Under the terms of the Purchase Agreement, if Lehman terminates the Purchase Agreement in the event that (1) we or Equity Residential breach any covenant or agreement under the Purchase Agreement, where the effect of the breach causes the closing conditions to be incapable of being satisfied, and, if the breach is capable of being cured, the breach is not cured by us or Equity Residential within 20 business days after receipt of notice from Lehman, (2) any event occurs that makes it impossible to satisfy a condition precedent to Lehman's obligation to close the transaction and Lehman and Archstone are not then in breach of representations, warranties, covenants or other agreements thereunder that would result in the conditions precedent to our obligations and Equity

Residential's obligations not being satisfied, or (3) we or Equity Residential breach our obligation to close the acquisition at a time when all closing conditions have been satisfied or waived, then we and Equity Residential will be jointly and severally obligated to pay a termination fee of $650.0 million. If we or Equity Residential extend the closing beyond the 60^th day following the execution of the Purchase Agreement and such events occur, the termination fee increases to $800.0 million. The termination fee will be Lehman's sole and exclusive remedy for a breach under the Purchase Agreement. Neither we nor Equity Residential can terminate the Purchase Agreement or fail to close when all the closing conditions have been satisfied without incurring the termination fee.

          Although we and Equity Residential are jointly and severally liable for liabilities assumed in the Archstone Portfolio Acquisition as well as the termination fee, if it is payable, we have separately agreed with Equity Residential that such liabilities, fees and expenses will generally be apportioned 40% to us and 60% to Equity Residential. Among the matters that we and Equity Residential have agreed to apportion 40% to us and 60% to Equity Residential are obligations that arise from the redemption of preferred equity obligations issued by two Archstone entities pursuant to the terms of those preferred equity obligations. Certain liabilities to be assumed pursuant to the Purchase Agreement are allocated solely to us or solely to Equity Residential, generally because the liability relates to one or more properties to be acquired by us or Equity Residential. If the termination of the Purchase Agreement is a result of a breach by either us or Equity Residential, then the breaching party shall be solely responsible for, and shall indemnify the non-breaching party against, the fees and expenses, including the termination fee, payable to Lehman resulting from a failure to consummate the acquisition, and any costs and expenses incurred by the non-breaching party in connection with enforcing its rights against the breaching party.

          Assets and liabilities of Archstone that are not acquired or assumed directly or indirectly wholly by either us or Equity Residential will be acquired through joint venture arrangements to be entered into by and between us and Equity Residential prior to or contemporaneously with the closing of the acquisition. One set of assets and liabilities to be acquired through joint venture arrangements consists of properties which we will jointly evaluate how best to manage after the closing, which may result (i) in the ultimate transfer to either us or Equity Residential when all necessary consents have been obtained and other transfer conditions satisfied, (ii) in continued joint ownership for a period, or (iii) in sale to a third party or parties. A second set of assets and liabilities to be acquired through joint venture arrangements consists of properties subject to contractual commitments to third parties to make certain payments in the event that taxable gain is recognized with respect to that property, which will be acquired in a transaction that should not recognize taxable gain. We then intend to contribute these properties, without the recognition of taxable gains, to limited partnerships or other entities controlled solely by either us or Equity Residential in exchange for passive interests in such limited partnership or other entities, which will eventually be the only assets of the joint venture. The properties designated for contribution to us are included in the operating properties table starting on page S-5 of this prospectus supplement.

Registration Rights Agreement and Shareholders Agreement

          In connection with the closing of the Archstone Portfolio Acquisition, we will enter into a registration rights agreement with Lehman, or the Registration Rights Agreement, pursuant to which we will be required to register under the Securities Act of 1933, as amended, or the Securities Act, the resale of the 14,889,706 shares of common stock we will issue to Archstone at the closing of the Archstone Portfolio Acquisition. Under the Registration Rights Agreement we will be obligated to file a resale shelf registration statement within 10 days following the closing pursuant to which, after the expiration of Lehman's lock-up described below on April 26, 2013, it will be able to sell, generally without restrictions, shares received in the transaction. We have the right to suspend sales under the shelf registration statement in limited circumstances for up to 90 days in any twelve-month period. We

are obligated to maintain the effectiveness of the registration statement until the earlier of the fifth anniversary of the closing of the Archstone Portfolio Acquisition or when Lehman owns less than $250.0 million of the shares it originally received under the Purchase Agreement.

          The Registration Rights Agreement gives Lehman the right to conduct two underwritten offerings of our shares each year. We will be obligated to cooperate with, and assist in, those offerings and to enter into a 30-day lock-up with Lehman's underwriters. Following the first anniversary of the closing, we will have the right once in any twelve-month period to delay an underwritten offering requested by Lehman so that we may undertake our own underwritten offering. If we effect an underwritten offering of our shares, Lehman has agreed to enter into a 30-day lock-up with the underwriters so long as it owns over 5% of our outstanding shares.

          Further, pursuant to a shareholders agreement we will enter into between us and Lehman, or the Shareholders Agreement, Lehman has agreed to a 150-day lock-up, starting from the date of the Purchase Agreement, with respect to the shares of common stock acquired in connection with the Archstone Portfolio Acquisition. Under the Shareholders Agreement, so long as Lehman owns more than 5% of our common stock, Lehman has agreed it will not (i) acquire beneficial ownership of any additional shares of our common stock; (ii) participate in any voting or similar arrangement with a third party; (iii) enter into, propose or facilitate any change in control transaction (or other extraordinary transaction involving us); or (iv) otherwise act, alone or in concert with others, to seek to control, or influence, our board of directors or our management or policies.

          Additionally under the Shareholders Agreement, for one year starting from the date of the closing of the Archstone Portfolio Acquisition, Lehman will vote all of its shares of our common stock in accordance with the recommendation of our board of directors on any matter other than an extraordinary transaction. After the first year, and for so long as Lehman holds more than 5% of our common stock, Lehman will vote all of its shares of our common stock (i) in accordance with the recommendations of our board of directors with respect to any election of directors, compensation and equity plan matters, and any amendment to our charter to increase our authorized capital stock; (ii) on all matters proposed by other shareholders, either proportionately in accordance with the votes of the other shareholders or, at its election, in accordance with the recommendation of our board of directors; and (iii) on all other matters, in its sole and absolute discretion.

          Prior to the issuance of our shares of common stock to Archstone, we will waive the stock ownership limit in our charter, which generally prohibits a stockholder from holding more than 9.8% of the issued and outstanding shares of any class or series of our stock, and will instead permit Lehman to hold the 14,889,706 shares of our common stock received in the Archstone Portfolio Acquisition, plus the shares they owned as of the date of the waiver. We will grant this waiver based on our belief that such waiver will not jeopardize our ability to qualify as a REIT.

          The summaries of the Purchase Agreement, the Registration Rights Agreement and the Shareholders Agreement are qualified in their entirety by reference to the Purchase Agreement, the Registration Rights Agreement, and the Shareholders Agreement which have been filed as exhibits to our Current Report on Form 8-K filed with the SEC on November 26, 2012.

Bridge Loan Facility

          In connection with the Archstone Portfolio Acquisition, on November 26, 2012, we received a commitment letter from Goldman Sachs Lending Partners LLC for a senior unsecured bridge loan facility, or the Bridge Loan Facility, in an aggregate principal amount of up to $2.2 billion, less the sum of the net proceeds from an equity offering, an offering of certain debt securities and/or any other bank or similar term loan financing and the aggregate principal amount of debt that we assume in connection with the Archstone Portfolio Acquisition for which lender consents have been obtained.

          The Bridge Loan Facility would mature 364 days from the date of funding and any loans provided under the Bridge Loan Facility are to be used to fund the Archstone Portfolio Acquisition and related costs, fees and expenses, including the repayment of certain debt we assume in connection with the Archstone Portfolio Acquisition. The loans under the Bridge Loan Facility must be funded on or before the date the Archstone Portfolio Acquisition closes, and will only be funded, if requested by us, upon the satisfaction of certain customary conditions to funding for this type of facility, including a condition that we shall have used commercially reasonable efforts to raise capital through an equity offering. Because the conditions to the lender's obligations under the Bridge Loan Facility are substantially similar to the conditions to our obligations under the Purchase Agreement, other than closing conditions that are customary for lending transactions such as the Bridge Loan Facility, we do not believe that there would be circumstances under which we would be obligated to complete the Archstone Portfolio Acquisition without also being able to obtain the funds to be borrowed under the Bridge Loan Facility.

          Loans under the Bridge Loan Facility will bear interest at a rate per annum equal to either (i) the reserve adjusted LIBOR rate or (ii) the base rate, plus an applicable margin based on the credit ratings of our unsecured and unsubordinated long-term indebtedness. The Bridge Loan Facility will also require us to pay Goldman Sachs Lending Partners LLC certain customary fees.

          The above summary of the Bridge Loan Facility is based on the commitment letter we received from Goldman Sachs Lending Partners LLC, the terms of which are subject to the final documentation between us and Goldman Sachs Lending Partners LLC.

THE OFFERING

          The number of shares of common stock to be outstanding after this offering is based upon 97,707,876 shares outstanding as of November 23, 2012.

          Unless we specifically state otherwise, the information in this prospectus supplement does not take into account the sale of up to 2,175,000 shares of common stock that the underwriters have the option to purchase from us to cover over-allotments.