Press Release

CoreSite Announces Completion of SSAE 16 Examination for all 14 North American Data Centers

Thorough external review validates optimal security and environmental controls provided to data center customers by CoreSite

DENVER, CO – September 18, 2012 – CoreSite Realty Corporation (NYSE: COR), a national provider of powerful, network-rich data centers, today announced the company has completed Statement on Standards for Attestation Engagements (SSAE) 16 Type 2 examinations covering 14 operational data centers. SSAE 16 provides CoreSite data center customers with assurance of corporate controls and validation of CoreSite's commitment to the most stringent standards of operational excellence. BrightLine, a licensed CPA firm, conducted the CoreSite SSAE 16 examinations over the twelve-month period that ended June 30, 2012. Additionally this is the second year that CoreSite has achieved greater than "six nines" of availability (99.9999%) across its North American facilities, having first achieved this designation in 2011 and again in 2012.

SSAE 16 is an attestation standard issued by the American Institute of Certified Public Accountants (AICPA) that reports on CoreSite controls supporting the services provided to customers. CoreSite management developed internal control objectives to support first-class data center management services that were used to complete the audit. Companies that are compliance-sensitive and may require an SSAE 16 include publicly-traded enterprises, financial firms, and healthcare organizations. The SSAE 16 examination report includes management's description of CoreSite's systems and the suitability of the design and operating effectiveness of the controls. Further, the report contains a written assertion from management regarding the systems and a services auditor's opinion letter.

"We are very proud to have completed the SSAE 16 examinations at all of the CoreSite facilities," said Dominic Tobin, Senior Vice President of Operations at CoreSite. "Our data centers are home to the vital data and infrastructure of more than 750 customers, many of whom maintain extremely rigorous compliance mandates. We are pleased to provide validation and confirmation of our operational excellence and security controls."

About CoreSite

CoreSite Realty Corporation (NYSE:COR) delivers secure, reliable, high-performance data center and interconnection solutions to a growing customer community across eight key North American markets. More than 1,200 of the world’s leading enterprises, network operators, cloud providers, and supporting service providers choose CoreSite to connect, protect and optimize their performance-sensitive data, applications and computing workloads. Our scalable, flexible solutions and 450+ dedicated employees consistently deliver unmatched data center options — all of which leads to a best-in-class customer experience and lasting relationships. For more information, visit www.CoreSite.com.

CoreSite Media Contact

Christine Shriver
Media Relations Manager
720.446.2023
christine.shriver@coresite.com

Forward Looking Statements

This press release may contain forward-looking statements within the meaning of the federal securities laws. Forward-looking statements relate to expectations, beliefs, projections, future plans and strategies, anticipated events or trends and similar expressions concerning matters that are not historical facts. In some cases, you can identify forward-looking statements by the use of forward-looking terminology such as "believes," "expects," "may," "will," "should," "seeks," "approximately," "intends," "plans," "pro forma," "estimates" or "anticipates" or the negative of these words and phrases or similar words or phrases that are predictions of or indicate future events or trends and that do not relate solely to historical matters. Forward-looking statements involve known and unknown risks, uncertainties, assumptions and contingencies, many of which are beyond CoreSite's control, that may cause actual results to differ significantly from those expressed in any forward-looking statement. These risks include, without limitation: the geographic concentration of CoreSite's data centers in certain markets and any adverse developments in local economic conditions or the demand for data center space in these markets; fluctuations in interest rates and increased operating costs; difficulties in identifying properties to acquire and completing acquisitions; significant industry competition; CoreSite's failure to obtain necessary outside financing; CoreSite's failure to qualify or maintain its status as a REIT; financial market fluctuations; changes in real estate and zoning laws and increases in real property tax rates; and other factors affecting the real estate industry generally. All forward-looking statements reflect CoreSite's good faith beliefs, assumptions and expectations, but they are not guarantees of future performance. Furthermore, CoreSite disclaims any obligation to publicly update or revise any forward-looking statement to reflect changes in underlying assumptions or factors, of new information, data or methods, future events or other changes. For a further discussion of these and other factors that could cause CoreSite's future results to differ materially from any forward-looking statements, see the section entitled "Risk Factors" in CoreSite's most recent annual report on Form 10-K, and other risks described in documents subsequently filed by CoreSite from time to time with the Securities and Exchange Commission.