Washington, D.C. 20549 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Form 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2026 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Transition Period from to Westlake Corporation (Exact name of Registrant as specified in its charter) Delaware 76-0346924 (State or other jurisdiction of incorporation or organization) (I.R.S. ...