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):

September 14, 2017 (September 13, 2017)

SL Green Realty Corp.

(EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

SL Green Operating Partnership, L.P.

(EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

Reckson Operating Partnership, L.P.

(EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

(212) 594-2700

(REGISTRANTS’ 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:

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))

Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company     o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act o

Item 8.01. Other Events

3.00% Exchangeable Senior Notes due 2017 — Exchange Period Prior to Maturity Date

The 3.00% Exchangeable Senior Notes due 2017 (the “Notes”) issued by SL Green Operating Partnership, L.P. (the “Issuer”) and guaranteed by Reckson Operating Partnership, L.P. (the “Guarantor”) are governed by the Indenture dated as of October 12, 2010 (the “Indenture”) entered into between the Issuer, the Guarantor, SL Green Realty Corp. (the “Company”) and The Bank of New York Mellon (the “Trustee”).

The Maturity Date of the Notes is October 16, 2017.

The Company hereby announces that the Notes are exchangeable, at the option of the holders thereof, from September 14, 2017 (being the 22nd Scheduled Trading Day prior to the Maturity Date) to the close of business on October 12, 2017 (being the second Business Day immediately preceding the Maturity Date). Holders of the Notes may surrender their Notes for exchange upon the terms and conditions of, and pursuant to the procedures set forth in, the Indenture.

The Company further announces that, pursuant to Section 15.10(d) of the Indenture, the Issuer has notified the Trustee in writing that the Cash Percentage shall be 100%. Therefore, pursuant to Section 15.10(b) and (d) of the Indenture, in respect of any Notes tendered for exchange in accordance with their terms, the Issuer shall, on the Maturity Date, settle its obligations in respect of any such Notes entirely in cash.

As referred to in the Indenture, the first day of the Applicable Observation Period is September 14, 2017 and the last day of the Applicable Observation Period is October 11, 2017.

Capitalized terms used but not defined herein shall have the meaning given to such terms in the Indenture.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrants have duly caused this report to be signed on their behalf by the undersigned hereunto duly authorized.

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