Common Stock

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):

March 4, 2026

SL GREEN REALTY CORP.

SL GREEN OPERATING PARTNERSHIP, L.P.

(Exact Name of Registrant as Specified in Charter)

One Vanderbilt Avenue
New York, New York 10017

(Address of principal executive offices, including zip code)

(212) 594-2700

(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 (see General Instruction A.2.):

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

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

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

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

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company 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 ¨

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. ¨

Thirty-Second Amendment to the First Amended and Restated Agreement of Limited Partnership of SL Green Operating Partnership, L.P.

On March 4, 2026, SL Green Realty Corp. (the “Company”), as the general partner of SL Green Operating Partnership, L.P. (the “Operating Partnership”), entered into a thirty-second amendment (the “Thirty-Second Amendment”) to the Operating Partnership’s First Amended and Restated Agreement of Limited Partnership, dated August 20, 1997 (as amended through the date hereof, the “Partnership Agreement”), in respect of the issuance of 252,000 Series Y Preferred Units of the Operating Partnership (the “Series Y Preferred Units”) of limited partnership interests with a liquidation preference of $25.00 per unit (the “Series Y Liquidation Preference”). 252,000 Series Y Preferred Units have been issued as a portion of the consideration for the acquisition of ownership interests in certain commercial real estate property. The Series Y Preferred Units are not convertible into or exchangeable for any other property or securities of the Partnership or the Company.

The Series Y Preferred Units provide for a fixed annual cash distribution of 5.00% of the Series Y Liquidation Preference per annum.

The Series Y Preferred Units were issued in reliance on the exemption from registration provided by Section 4(a)(2) of the Securities Act of 1933, as amended.

The foregoing description of the Thirty-Second Amendment is qualified in its entirety by reference to the Thirty-Second Amendment, a copy of which is filed herewith as Exhibit 10.1 and incorporated herein by reference.

The information set forth above under Item 1.01 is incorporated by reference herein with respect to the issuance by the Operating Partnership of 252,000 Series Y Preferred Units.

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.

Date: March 6, 2026