Corporate Office Properties Trust (COPT) (NYSE: OFC), announces that its operating partnership, Corporate Office Properties, L.P. (the "Operating Partnership" and, together with COPT, the “Company”), has commenced a registered exchange offer to exchange any and all of its outstanding 3.600% Senior Notes due 2023, which were issued in a private placement (the “Private Notes”), for an equal principal amount of new 3.600% Senior Notes due 2023 that have been registered under the Securities Act of 1933, as amended (the “Registered Notes”). The sole purpose of the exchange offer is to fulfill the Company’s obligations with respect to exchanging the Private Notes for registered notes. Pursuant to a registration rights agreement entered into by the Operating Partnership and COPT in connection with the sale of the Private Notes, the Company agreed to file with the Securities and Exchange Commission a registration statement relating to the exchange offer pursuant to which the Operating Partnership would offer to exchange any Private Notes tendered by the holders of those notes for Registered Notes containing terms that are substantially identical to the Private Notes. Any Private Notes not tendered for exchange in the exchange offer will remain outstanding and continue to accrue interest, but will not retain any rights under the registration rights agreement except in limited circumstances. The terms of the exchange offer are contained in the exchange offer prospectus dated July 16, 2013. The exchange offer will expire at 5:00 p.m., New York City time, August 14, 2013, unless extended. Private Notes tendered pursuant to the exchange offer may be withdrawn at any time prior to the expiration date by following the procedures set forth in the exchange offer prospectus. Requests for assistance or for copies of the exchange offer prospectus should be directed to the exchange agent: U.S. Bank National Association, Global Corporate Trust Services, 1021 East Cary Street, Richmond, VA 23219, Attention: Becky D. Burton Corporate Trust Department, Reference: Corporate Office Properties Trust, 3.600% Senior Notes due 2023.