Westlake Corporation (NYSE: WLK) (“Westlake”) announced today that it has completed the acquisition of the global compounding solutions businesses of the ACI/Perplastic Group (collectively, “ACI”). Headquartered in Portugal, ACI is a global manufacturer of specialty materials, primarily serving the wire and cable sectors. “The integration of ACI with Westlake’s compounding operations represents a strong strategic alignment, offering significant opportunities to further strengthen our Housing & Infrastructure Products (HIP) business. This acquisition will enhance the reach of Westlake Global Compounds and introduce new specialty products and advanced technologies to our portfolio,” stated Jean-Marc Gilson, President and Chief Executive Officer of Westlake. “ACI has built an impressive reputation for delivering innovative, high-value solutions,” said Maribel Wilson, Vice President of Westlake Global Compounds. “We are excited to welcome their skilled team to Westlake and look

Westlake Corporation (NYSE: WLK) (“Westlake”) (the “Company”) announced today that the Company has approved a plan to cease operation of certain of the Company’s North American chlorovinyl production facilities, including: its polyvinyl chloride (“PVC”) plant at the Aberdeen, Mississippi site, which has an annual capacity of approximately 1 billion pounds of suspension PVC resin; its vinyl chloride monomer (“VCM”) plant at the Lake Charles, Louisiana North site, which has an annual capacity of approximately 910 million pounds of VCM; and one of its diaphragm chlor-alkali units at the Lake Charles, Louisiana South site, which has an annual capacity of approximately 825 million pounds of chlorine and 910 million pounds of caustic soda. The Company plans to continue supplying customers with PVC, VCM and chlor-alkali products from its seven other North American chlorovinyl facilities. Following the closures, the Company expects to have aggregate annual production capacity of approximately

Westlake Corporation (NYSE: WLK) today released its 2024 Sustainability Report , marking the company’s eighth consecutive annual update on its voluntary sustainability initiatives and ongoing operational improvements. The report highlights that Westlake has successfully met its target to reduce Scope 1 and Scope 2 CO 2 e emissions per ton of production by 20% compared to its 2016 baseline. “At Westlake, we are deeply committed to sustainability and continuous improvement. Achieving our goal of reducing Scope 1 and Scope 2 CO 2 e emissions per ton of production by 20% from our 2016 baseline reflects the dedication and innovative spirit of our entire team,” said Jean-Marc Gilson, President and Chief Executive Officer at Westlake Corporation. “This milestone demonstrates our ongoing efforts to drive meaningful change for our business, our communities, and the environment.” Having reached its initial 2030 emissions target, Westlake is now committed to further decreasing its Scope 1 and

$0.53 per share dividend declared payable on December 11, 2025 The Board of Directors of Westlake Corporation (NYSE: WLK) today declared a regular dividend distribution of $0.53 per share for the third quarter of 2025. This dividend will be payable on December 11, 2025 to stockholders of record on November 25, 2025. Westlake announced its first dividend on November 11, 2004 and has successively been paying and increasing its dividend for the past 21 years. The statements in this release that are not historical facts, including statements regarding future payment of dividend, are forward-looking statements. These forward-looking statements are subject to significant risks and uncertainties. For more detailed information about the factors that could cause actual results to differ materially, please refer to Westlake’s Annual Report on Form 10-K for the year ended December 31, 2024, which was filed with the SEC in February 2025, and Westlake’s Quarterly Report on Form 10-Q for the

Westlake Corporation (NYSE: WLK) (“Westlake”) today announced the expiration and results of its cash tender offer to purchase (the “Offer”) any and all of the outstanding 3.600% Senior Notes due 2026 (the “Notes”). The tender offer described herein was made on the terms and subject to the conditions set forth in the Offer to Purchase, dated November 4, 2025 (the “Offer to Purchase”) and the related Notice of Guaranteed Delivery. Capitalized terms used but not defined in this announcement have the meanings given to them in the Offer to Purchase. The tender offer expired at 5:00 p.m., New York City time, on November 10, 2025 (the “Expiration Date”). The settlement date for the Offer will be on or about November 12, 2025 (the “Settlement Date”). According to information provided by Global Bondholder Services Corporation, $253,730,000 aggregate principal amount of the Notes were validly tendered (other than pursuant to the guaranteed delivery procedures set forth in the Offer to Purchase

Westlake Corporation (NYSE: WLK) (“Westlake”) today announced the pricing of its cash tender offer to purchase (the “Offer”) any and all of the outstanding 3.600% Senior Notes due 2026 (the “Notes”) on the terms set forth in the table below. The table below sets forth the applicable Reference Yield and Consideration for the Notes, as calculated at 2:00 p.m., New York City time, today, November 10, 2025, in accordance with the Offer to Purchase (as defined below). Series of Notes CUSIP Numbers(1) Aggregate Principal Amount Outstanding U.S. Treasury Reference Security(2) Reference Yield Bloomberg Reference Page(2) Fixed Spread(2) Consideration(2) 3.600% Senior Notes due 2026 960413AT9 (Registered) 960413AH5 (Rule 144A) U96060AC9 (Reg. S) $750,000,000 4.375% UST due 8/15/2026 3.741% FIT3 35 bps $996.32 (1) No representation is made as to the correctness or accuracy of the CUSIP numbers listed in this press release. Such information is provided solely for the convenience of holders of the