UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF ☐ 1934 Commission File Number 001-32641 BROOKDALE SENIOR LIVING INC. (Exact name of registrant as specified in its charter) Delaware 20-3068069 State or other jurisdiction of (I.R.S. Employer Identification No.) ...