Westlake Corporation announced the pricing of its cash tender offer to purchase any and all of the outstanding 3.600% Senior Notes due 2026 (the ?Notes?). Series of Notes: 3.600% Senior Notes due 2026. Aggregate Principal Amount Outstanding: $750,000,000.

The tender offer is being made solely pursuant to the terms and conditions set forth in an Offer to Purchase, dated November 4, 2025 (the ?Offer to Purchase?). Holders of the Notes are urged to carefully read the Offer to Purchase before making any decision with respect to the tender offer. The tender offer is not conditioned on any minimum amount of the Notes being tendered.

Subject to applicable law, Westlake may amend, extend or terminate the tender offer in its sole discretion. Capitalized terms used but not defined in this announcement have the meanings given to them in the Offer to Purchase. The tender offer will expire at 5:00 p.m., New York City time, November 10, 2025, unless extended or terminated by Westlake (such time and date, as the same may be extended or terminated by Westlake in its sole discretion, subject to applicable law, the ?Expiration Date?).

Tendered Notes may be withdrawn at or prior to the Expiration Date by following the procedures in the Offer to Purchase, but may not thereafter be validly withdrawn, unless otherwise required by applicable law. Holders of Notes must validly tender and not validly withdraw their Notes, or submit a Notice of Guaranteed Delivery and comply with the related procedures, prior to the Expiration Date in order to be eligible to receive the Consideration. Accrued and unpaid interest will be paid on all Notes validly tendered and accepted for purchase pursuant to the Offer, including Notes accepted pursuant to the guaranteed delivery procedures described in the Offer to Purchase (the ?Guaranteed Delivery Procedures?), from the last interest payment date up to, but not including, the settlement date, which is expected to be on or about November 12, 2025.

Westlake expects to pay the Consideration plus accrued interest for all Notes validly tendered and accepted for purchase (other than Notes tendered pursuant to the Guaranteed Delivery Procedures) on the Settlement Date. For holders who deliver a Notice of Guaranteed Delivery and all other required documentation at or prior to the Expiration Date, upon the terms and subject to the conditions set forth in the Offer to Purchase, the deadline to validly tender their Notes using the Guaranteed Delivery Procedures will be the second business day after the Expiration Date and is expected to be 5:00 p.m., New York City time, on November 13, 2025. Westlake expects to pay the Consideration plus accrued interest for all Notes validly tendered and accepted for purchase pursuant to the Guaranteed Delivery Procedures on or about November 14, 2025, the third business day after the Expiration Date.