UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 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): September 4, 2013

Gramercy Property Trust Inc.

(Exact Name of Registrant as Specified in its Charter)

(212) 297-1000

(Registrant’s Telephone Number, including Area Code)

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:

On September 4, 2013, GPT Property Trust LP (the “Borrower”), the operating subsidiary of Gramercy Property Trust Inc. (the “Company”), entered into a Credit and Guaranty Agreement (the “Credit Agreement”), by and among the Borrower, the Company and certain of its subsidiaries, as guarantors, the lenders party thereto from time to time, Deutsche Bank AG New York Branch as administrative agent and Deutsche Bank Securities Inc. as lead arranger and bookrunner.

The Credit Agreement provides for a $100,000,000 senior secured revolving credit facility with an accordion feature, subject to certain exceptions, to increase the facility to $150,000,000 (the “Credit Facility”). The Credit Facility has an initial term of two years with an option for a one-year extension. Advances under the Credit Facility will incur interest at a floating rate equal to LIBOR plus a spread between 190 and 275 basis points depending upon the Company’s overall leverage ratio. The Credit Facility will have an initial borrowing rate of LIBOR plus 190 basis points. The Credit Facility is guaranteed by the Company and certain of its subsidiaries and will be secured by first priority mortgages on properties (to be designated from time to time) that make up the borrowing base (the “Borrowing Base”). Availability under the Credit Facility is limited to the lesser of $100 million or 60% of the value of the Borrowing Base. As of the execution of the Credit Agreement, no properties were designated as Borrowing Base properties, and currently there is no borrowing outstanding or available under the Credit Facility. The parties anticipate designating the initial Borrowing Base properties under the Credit Agreement within the next several weeks. Thereafter, Borrowing Base properties may be removed or additional properties may be designated as Borrowing Base properties from time to time.

The Credit Agreement contains certain affirmative and negative covenants that are binding on the Borrower and each guarantor (which are in some cases subject to exceptions), including, but not limited to, restrictions on (i) liens, (ii) indebtedness, (iii) mergers and acquisitions, (iv) asset sales, (v) investments and capital expenditures, (vi) restricted payments including dividends and stock repurchases, (vii) modifications to organizational documents, (viii) changes in nature of business, and (ix) transactions with affiliates.

In addition, the Credit Agreement requires the Borrower to comply with certain financial covenants, which are measured at the level of the Company and calculated for the Company and its subsidiaries on a consolidated basis, as follows:

The Credit Agreement contains customary events of default (which are in some cases subject to certain exceptions, thresholds, notice requirements and grace periods), including, but not limited to, nonpayment of principal or interest, failure to perform or observe covenants, breaches of representations and warranties, cross-defaults with certain other agreements or indebtedness, final judgments or orders, certain bankruptcy-related events or other relief proceedings or a change of control of the Company.

The foregoing does not constitute a complete summary of the terms of the Credit Agreement and reference is made to the complete text of the governing document, which is filed as Exhibit 10.1 to this Current Report on Form 8-K.

The information set forth in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 2.03.

(d) Exhibits

Exhibit No.

Signature

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.

EXHIBIT INDEX