UPDATE: CoreSite Realty Corporation Announces Pricing of 4,000,000 Shares of 7.25% Series A Cumulative Redeemable Preferred Stock

CoreSite Realty Corporation

, an owner, developer and operator of strategically located data centers in some of the leading communications hubs in North America, today announced the pricing of an underwritten public offering of 4,000,000 shares of 7.25% Series A Cumulative Redeemable Preferred Stock at a price of $25.00 per share for gross proceeds of $100 million. The offering is expected to close on December 12, 2012, subject to closing conditions. The Company has granted the underwriters a 30-day option to purchase up to an additional 600,000 shares of its 7.25% Series A Cumulative Redeemable Preferred Stock to cover over-allotments, if any. The Company intends to apply to list the shares on the New York Stock Exchange. The Company intends to contribute the net proceeds from this offering to its operating partnership, CoreSite, L.P., which will subsequently use the net proceeds received from the Company to temporarily repay borrowings under its revolving credit facility, to repay the full amount of the mortgage loan payable on its 12100 Sunrise Valley property and for general corporate purposes, which could include the acquisition of additional properties or to fund development and redevelopment opportunities. The offering is being made pursuant to an effective shelf registration statement, prospectus and related prospectus supplement filed by the Company with the Securities and Exchange Commission. Citigroup Global Markets Inc., Merrill Lynch, Pierce, Fenner & Smith Incorporated and RBC Capital Markets, LLC are the joint book-running managers for the offering. Credit Suisse Securities (USA) LLC and KeyBanc Capital Markets Inc. are the co- managers for the offering. A copy of the prospectus supplement and the accompanying prospectus relating to these securities may be obtained, when available, by contacting Citigroup, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717 (tel: 800-831-9146) or email: batprospectusdept@citi.com; Merrill Lynch, Pierce, Fenner & Smith Incorporated, 222 Broadway, 7th Floor, New York, NY 10038, attention: Prospectus Department, or e-mail dg.prospectus_requests@baml.com. Phone: 1-800-294-1322; RBC Capital Markets, LLC, Attention: Prospectus Department, Three World Financial Center, 200 Vesey Street, 8th floor, New York, New York 10281-8098, (866) 375-6829, rbcnyfixedincomeprospectus@rbccm.com; Credit Suisse Securities (USA) LLC, One Madison Avenue, New York, NY 10010, Attn: Prospectus Department. Phone: 1-800-221-1037; KeyBanc Capital Markets Inc., Phone: (866) 227-6479. This press release is for informational purposes only and is not an offer to sell or the solicitation of an offer to buy with respect to any securities in any jurisdiction in which such offer, solicitation or sale would be unlawful. The offering is not being made in any jurisdiction in which the making or acceptance thereof would not be in compliance with the securities, blue sky or other laws of such jurisdiction.