VMRK: Other company developments

Item 8.01 Other Events. On September 16, 2026, Vivmark Residential’s operating partnership, ERP Operating Limited Partnership, an Illinois limited partnership (the “Operating Partnership”), increased the maximum aggregate amount for which it may issue, from time to time, unsecured notes (the “Notes”) pursuant to its U.S. dollar-denominated commercial paper program from a maximum aggregate amount outstanding at any time of $1.5 billion to $2.5 billion. The Notes are sold under customary terms in the United States commercial paper note market and rank pari passu with all of the Operating Partnership’s other unsecured senior indebtedness. The Notes have not been and will not be registered under the Securities Act of 1933, as amended (the “Securities Act”), or state securities laws and may not be offered or sold in the United States absent registration or an applicable exemption from the registration requirements of the Securities Act and applicable state laws. The Notes are being sold pursuant to the exemption from registration contained in Section 4(a)(2) of the Securities Act. The information contained in this Current Report on Form 8-K is neither an offer to sell nor a solicitation of an offer to buy any securities. SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, each registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. VIVMARK RESIDENTIAL Date: September 17, 2026 By: /s/ Scott J. Fenster Name: Scott J. Fenster Its: Executive Vice President, General Counsel and Corporate Secretary ERP OPERATING LIMITED PARTNERSHIP By: Vivmark Residential, its general partner Date: September 17, 2026 By: /s/ Scott J. Fenster Name: Scott J. Fenster Its: Executive Vice President, General Counsel and C