Westlake Corporation

WLK·NYSE·$88.77Share Price as of 11/2·$11BMarket Cap as of 11/2

Financials

10-QQ2 ended 06/30/2608/05/26 10-QQ1 ended 03/31/2605/06/26 10-KFY 202502/26/26 10-QQ3 ended 09/30/2510/31/25 10-QQ2 ended 06/30/2508/06/25

Disclosures

8-KCurrent report09/29/26 8-KChange in Directors or Officers08/31/26 8-KResults of Operations; Regulation FD Disclosure08/04/26 8-KOther Events07/29/26 8-KCurrent report06/15/26

Prospectuses and Registrations

424B5Prospectus supplement11/05/25 424B5Prospectus supplement11/04/25 FWPFree writing prospectus11/04/25 S-3ASRAutomatic shelf registration10/31/25 S-8Registration of securities for employees05/11/23

Proxies

DEF 14ADefinitive proxy04/02/26 DEFA14AAdditional proxy materials04/02/26 DEF 14ADefinitive proxy03/28/25 DEFA14AAdditional proxy materials03/28/25 PX14A6GLetter to shareholders04/11/24

Ownership

Form 4Insider transaction09/01/26 Form 3Initial insider ownership08/31/26 Form 4Insider transaction08/17/26 Form 4Insider transaction08/17/26 Form 4Insider transaction08/17/26

Other

8-A12B8-A12B08/21/26 CERTCEO/CFO certification08/21/26 SDConflict Minerals disclosure05/18/26 ARSAnnual report to shareholders04/02/26 SDConflict Minerals disclosure05/23/25