UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ________to _________ 001-13106 (Essex Property Trust, Inc.) 333-44467-01 (Essex Portfolio, L.P.) (Commission File Number) ESSEX PROPERTY TRUST, INC. ESSEX PORTFOLIO, ...