EXHIBIT 99.1 WESTLAKE CORPORATION Contact—(713) 960-9111 Investors—Steve Bender Media—L. Benjamin Ederington Westlake Corporation Reports First Quarter 2024 Results • Record first quarter Housing and Infrastructure Products (HIP) income from operations of $210 million with a 20% operating income margin • HIP EBITDA of $264 million rose 29% year-over-year with a record first quarter EBITDA margin of 25% • PEM sales volume grew 3% sequentially from gradual demand recovery with stable average sales prices HOUS ...