UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): May 20, 2015

CoreSite Realty Corporation

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (866) 777-2673

N/A

(Former name or former address if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 5.07.                Submission of Matters to a Vote of Security Holders.

The 2015 Annual Meeting of Stockholders of CoreSite Realty Corporation (the “Company”) was held on May 20, 2015, at which the Company’s stockholders voted on, and approved, the following proposals:

Proposal 1.  Election of directors, each to serve until the 2016 Annual Meeting of Stockholders or until a successor for each has been duly elected and qualified.

Proposal 2.  Ratification of the appointment of KPMG LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2015.

Proposal 3.  Advisory resolution to approve the compensation of the Company’s named executive officers.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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