Equity Office Files Proxy Statement Supplement With SEC

29 January 2007

CHICAGO – (BUSINESS WIRE) – Jan. 29, 2007 – Equity Office Properties Trust (NYSE: EOP) today filed a supplement to its definitive proxy statement with the SEC relating to the merger agreement with affiliates of The Blackstone Group, as amended. Under the terms of the amended agreement, Blackstone will acquire all of the outstanding common stock of Equity Office for $54.00 per share. Equity Office expects to begin to distribute copies of the proxy statement supplement promptly.

Equity Office’s Board of Trustees continues to recommend the approval of the transaction with Blackstone by Equity Office common shareholders. The special meeting of shareholders to vote on the merger agreement with affiliates of The Blackstone Group remains scheduled to be convened on February 5, 2007. If approved by shareholders, and subject to satisfaction of other closing conditions, the Blackstone transaction would be expected to close on or about February 8, 2007.

About Equity Office

Equity Office, operating through its various subsidiaries and affiliates, is the largest publicly traded owner and manager of office properties in the United States by square footage. At September 30, 2006, Equity Office had a national office portfolio comprised of whole or partial interests in 585 office buildings located in 16 states and the District of Columbia. As of that date, Equity Office had an ownership presence in 24 Metropolitan Statistical Areas (MSAs) and in 100 submarkets, enabling it to provide a wide range of office solutions for local, regional and national customers.

EOP Operating Limited Partnership is a Delaware limited partnership through which Equity Office conducts substantially all of its business and owns, either directly or indirectly through subsidiaries, substantially all of its assets.

Forward-Looking Statements

This press release contains certain forward-looking statements based on current Equity Office management expectations. Those forward-looking statements include all statements other than those made solely with respect to historical fact. Numerous risks, uncertainties and other factors may cause actual results, performance or transactions of Equity Office and its subsidiaries to differ materially from those expressed in any forward-looking statements. Factors include, but are not limited to: (1) the failure to satisfy the conditions to completion of the proposed mergers with affiliates of The Blackstone Group, including the receipt of the required shareholder approval; (2) the failure to obtain the necessary financing arrangements set forth in the commitment letters received by Blackhawk Parent LLC (an affiliate of The Blackstone Group) in connection with the proposed mergers and the actual terms of such financings; (3) the failure of the proposed mergers to close for any other reason; (4) the occurrence of any effect, event, development or change that could give rise to the termination of the merger agreement; (5) the outcome of the legal proceedings that have been, or may be, instituted against Equity Office and others following the announcement of the proposed mergers; (6) the risks that the proposed transactions disrupt current plans and operations including potential difficulties in employee retention; (7) the amount of the costs, fees, expenses and charges related to the proposed mergers; and (8) the substantial indebtedness that will need to be incurred to finance consummation of the proposed mergers and related transactions, including the tender offers and consent solicitations and other refinancings of Equity Office and its subsidiaries; and other risks that are set forth in the “Risk Factors,” “Legal Proceedings” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” sections of Equity Office’s and EOP Operating Limited Partnership’s filings with the Securities and Exchange Commission (“SEC”). Many of the factors that will determine the outcome of the subject matter of this press release are beyond Equity Office’s ability to control or predict. Equity Office undertakes no obligation to revise or update any forward-looking statements, or to make any other forward-looking statements, whether as a result of new information, future events or otherwise.

Additional Information About the Merger and Where to Find It

In connection with proposed merger transactions involving Equity Office and EOP Operating Limited Partnership and affiliates of The Blackstone Group, Equity Office filed a supplement to its definitive proxy statement with the SEC today and will furnish the proxy statement supplement to Equity Office’s shareholders. SHAREHOLDERS ARE URGED TO READ CAREFULLY THE PROXY STATEMENT AND THE PROXY STATEMENT SUPPLEMENT BECAUSE THEY CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED MERGER TRANSACTIONS. Shareholders can obtain the proxy statement, the proxy statement supplement and all other relevant documents filed by Equity Office with the SEC free of charge at the SEC’s website at http://www.sec.gov/ or from Equity Office Properties Trust, Investor Relations at Two North Riverside Plaza, Suite 2100, Chicago, Illinois, 60606, (800) 692-5304 or at http://www.equityoffice.com. The contents of the Equity Office website are not made part of this press release.

Participants in the Solicitation

Equity Office and its trustees and officers and other members of management and employees may be deemed to be participants in the solicitation of proxies in respect to the proposed merger transactions. Information about Equity Office and its trustees and executive officers, and their ownership of Equity Office’s securities, is set forth in the proxy statement and proxy statement supplement relating to the proposed merger transactions described above.