WLK SEC Filings: 8-K, 10-Q, S-3 & 424B – Westlake

Financials

TYPE

HEADLINE

FILED AT

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Nov 4, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Aug 5, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

May 6, 2026

10-K

Form 10-K - Annual report [Section 13 and 15(d), not S-K Item 405]

Feb 26, 2026

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Oct 31, 2025

10-Q

Form 10-Q - Quarterly report [Sections 13 or 15(d)]

Aug 6, 2025

News

TYPE

HEADLINE

FILED AT

8-K

Westlake Corporation Reports Third Quarter 2026 Results

Nov 4, 2026

8-K

Westlake to Close Cologne PVC Plant to Optimize European Chlorovinyls Footprint

Sep 29, 2026

8-K

Westlake Corporation Appoints Tommy E. Darby as Vice President and Chief Accounting Officer

Aug 31, 2026

8-K

Westlake Corporation Reports Second Quarter 2026 Financial Results

Aug 4, 2026

8-K

Westlake Corporation Receives Dismissal of Two Ethylene Antitrust Lawsuits in the Netherlands

Jul 29, 2026

8-K

Westlake Corporation Completes Acquisition of Wilhelmshaven PVC and VCM Production Site

Jun 15, 2026

Prospectus

TYPE

HEADLINE

FILED AT

424B5

FIXED PRICE OFFERING - SENIOR NOTES | Offering amount: $1,194,396,000 | Bank: BofA Securities

Nov 5, 2025

424B5

PENDING FIXED PRICE OFFERING | Bank: BofA Securities, Deutsche Bank Securities, J.P. Morgan, Wells Fargo Securities

Nov 4, 2025

424B5

Risks Related to the Common Stock-

Aug 6, 2021

424B5

Risks Related to the Common Stock-

Aug 5, 2021

424B5

Form 424B5 - Prospectus [Rule 424(b)(5)]

Jun 10, 2020

424B5

Form 424B5 - Prospectus [Rule 424(b)(5)]

Jun 9, 2020

Registrations

TYPE

HEADLINE

FILED AT

8-A12B

Form 8-A12B - Registration of securities [Section 12(b)]

Aug 21, 2026

FWP

Form FWP - Filing under Securities Act Rules 163/433 of free writing prospectuses

Nov 4, 2025

S-3ASR

Form S-3ASR - Automatic shelf registration statement of securities of well-known seasoned issuers

Oct 31, 2025

S-8

Form S-8 - Securities to be offered to employees in employee benefit plans

May 11, 2023

S-3ASR

SHELF

Nov 3, 2022

FWP

Form FWP - Filing under Securities Act Rules 163/433 of free writing prospectuses

Aug 5, 2021

Proxies

TYPE

HEADLINE

FILED AT

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

Apr 2, 2026

DEF 14A

Form DEF 14A - Other definitive proxy statements

Apr 2, 2026

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

Mar 28, 2025

DEF 14A

Form DEF 14A - Other definitive proxy statements

Mar 28, 2025

PX14A6G

Form PX14A6G - Notice of exempt solicitation submitted by non-management

Apr 11, 2024

DEFA14A

Form DEFA14A - Additional definitive proxy soliciting materials and Rule 14(a)(12) material

Mar 29, 2024

Ownerships

TYPE

HEADLINE

FILED AT

Darby Tommy (Reporting)

Sep 1, 2026

Darby Tommy (Reporting)

Aug 31, 2026

Sheets Jeffrey Wayne (Reporting)

Aug 17, 2026

Sabat Carolyn Chao (Reporting)

Aug 17, 2026

Patel Bhavesh V. (Reporting)

Aug 17, 2026

NORTHCUTT R BRUCE (Reporting)

Aug 17, 2026

Other

TYPE

HEADLINE

FILED AT

Form SD - Specialized disclosure report

May 18, 2026

Form SD - Specialized disclosure report

May 23, 2025

LETTER

Form UPLOAD - SEC-generated letter

Sep 6, 2024

CORRESP

Form CORRESP - Correspondence

Aug 22, 2024

LETTER

Form UPLOAD - SEC-generated letter

Aug 9, 2024

Form SD - Specialized disclosure report

May 21, 2024

Westlake Corporation WLK · SEC Filings