WESTLAKE CORP

Industrial Organic Chemicals

WLK Chemicals People in Chemicals SEC CIK 0001262823 ↗

Computed from SEC EDGAR filings and closing prices — not copied from any wealth ranking. Dataset . How we calculate this.

Market capitalisation
$9.05B
127,796,548 shares Covers every share class this company has on file.
Insiders on file
15
people who have filed Form 3, 4 or 5 naming this issuer
Value of insider-held stock
$74.73M
from the holdings reported on Forms 3/4/5; this figure has no separate as-of date on file
Insider-held share of market cap
0.83%
insider-held value divided by market capitalisation

What WESTLAKE CORP reports

Revenue and net income below are for fiscal period FY2025, the period label carried by this company’s own annual XBRL filings to the SEC. Fiscal years do not line up between companies — one company’s FY2026 can cover much the same months as another’s FY2025 — so compare the periods, not just the numbers.

Revenue
$11.17B
FY2025 annual revenue, from this company’s own annual XBRL filings to the SEC
Net income
-$1.51B
FY2025 a loss for the period, from this company’s own annual XBRL filings to the SEC
Employees
14,600
Yahoo Finance
Where the employee count comes from

Headcount comes from Yahoo Finance, not from a filing. The date beside it is the day we retrieved the figure — it is not the date the company counted its staff, and Yahoo does not publish that date. Unlike the SEC filings behind the other figures on this page, this one carries no open licence, so we publish the number and nothing else from that source.

Insiders at WESTLAKE CORP

Shares is what each person last reported holding here.

Everyone below has filed at least one insider report against this company.

Value is that share count priced at the same closing price used everywhere else on this site. A row priced from only some of a person’s securities says so — we do not quietly present a partial sum as a complete one.

Rows are grouped by the role each person reports.

The role comes from the relationship boxes a person ticks on their own insider filings — officer, director, ten per cent owner — not from anything we infer. Somebody who is both an officer and a director appears once, in the combined group, so the row count still matches the figure at the top of this page. Where no filing states a role we say so instead of guessing one.

People who file insider reports against WESTLAKE CORP.
Insider Reported role Shares Value Last action
Officers 5
L. Benjamin Ederington EVP 80,158 $6.00M F Shares withheld for taxes Feb 20, 2026 position reported
Robert F Buesinger EVP 34,482 $2.58M S Open-market sale Mar 27, 2026 position reported
Mark Steven Bender CFO 28,015 $2.10M F Shares withheld for taxes May 13, 2026 position reported
Thomas J Janssens SVP 17,127 $1.28M F Shares withheld for taxes Feb 21, 2025 position reported
Scott Thomas Szwejbka SVP 13,773 $1.03M F Shares withheld for taxes Feb 20, 2026 position reported
Officers who also sit on the board 2
Albert Chao Albert Chao Executive Chairman 642,880 $48.08M S Open-market sale Aug 11, 2026 position reported
James Chao James Chao Chairman 49,774 $3.72M F Shares withheld for taxes Feb 20, 2026 position reported
Directors 8
David Tsung-Hung Chao Board Member 28,335 $2.12M M Option exercise or conversion Aug 8, 2026 position reported
Catherine T Chao Board Member 25,003 $1.87M M Option exercise or conversion Aug 8, 2026 position reported
R. Bruce Northcutt Board Member 21,183 $1.58M M Option exercise or conversion Aug 8, 2026 position reported
Michael J Graff Board Member 21,142 $1.58M M Option exercise or conversion Aug 8, 2026 position reported
Jeffrey Wayne Sheets Jeffrey Wayne Sheets Board Member 12,759 $954.2K M Option exercise or conversion Aug 8, 2026 position reported
Kimberly S Lubel Board Member 11,653 $871.5K M Option exercise or conversion Aug 8, 2026 position reported
Marius Haas Board Member 11,631 $869.9K M Option exercise or conversion Aug 11, 2024 position reported
Roger A. Cregg Board Member 1,339 $100.1K M Option exercise or conversion Aug 8, 2026 position reported

Events from filings

Detected automatically in the filings linked below. Each headline is built from the numbers in those filings, not written by a model. Newest first; events older than 45 days stay listed and are marked as older.

WESTLAKE CORP (WLK) filed a Form 8-K under Item 5.02 (directors and officers) on Aug 31, 2026

Director or officer change filing

The company filed a current report that includes Item 5.02, the item used to report departures, elections or appointments of directors and certain officers, and related pay arrangements. We record only that this filing exists: we have not extracted who left, who joined or whose role changed. Open the filing to read it.

Form 8-K filed Aug 31, 2026, item 5.02. SEC filing ↗

Source: SEC EDGAR (United States); every row links to where it was published. Event computed Sep 14, 2026.

Mark Steven Bender sold 16,413 WESTLAKE CORP (WLK) shares for $1,847,119 on Mar 27, 2026

Unusual change in a direct holding

Flagged because the change that day in the shares this person holds directly was unusually large compared with their own earlier changes. The rows below are the open-market trades reported that day; under each share count is the balance the filing reports after that line.

Mark Steven Bender sold 16,413 WESTLAKE CORP (WLK) shares for $1,847,119 on Mar 27, 2026
Date Insider Transaction Shares Price Value Filing
Mar 27, 2026 Mark Steven Bender S Open-market sale 16,413 held after: 28,015 $112.54 $1,847,119 SEC filing ↗

Source: SEC EDGAR (United States); every row links to where it was published. Event computed Sep 14, 2026.

Mark Steven Bender sold 17,409 WESTLAKE CORP (WLK) shares for $1,756,999 on Feb 27, 2026

Unusual change in a direct holding

Flagged because the change that day in the shares this person holds directly was unusually large compared with their own earlier changes. The rows below are the open-market trades reported that day; under each share count is the balance the filing reports after that line.

Mark Steven Bender sold 17,409 WESTLAKE CORP (WLK) shares for $1,756,999 on Feb 27, 2026
Date Insider Transaction Shares Price Value Filing
Feb 27, 2026 Mark Steven Bender S Open-market sale 421 held after: 44,433 $101.52 $42,740 SEC filing ↗
Feb 27, 2026 Mark Steven Bender S Open-market sale 16,988 held after: 44,854 $100.91 $1,714,259 SEC filing ↗

Total of the rows above: $1,756,999, in the currency the filings report.

Source: SEC EDGAR (United States); every row links to where it was published. Event computed Sep 14, 2026.

Recent insider transactions

Of the 124 rows we hold, 1 are open-market purchases (P) and 14 open-market sales (S) — the only codes we count as buying or selling.

The rest — awards, shares withheld to pay tax, option exercises, gifts and so on — follow from an employment contract or a transfer arranged off-market, not from a decision to buy or sell, so counting them would turn this into a pay table.

A price of 0.00 is a real reported figure on gifts (G) and share awards (A) — not a gap in our data.

Insider transactions disclosed to the SEC for WESTLAKE CORP, newest first, each with the filing behind it.
Date Insider Transaction Shares Price Value Filing
Aug 11, 2026 Albert Chao S Open-market sale 31,384 $80.42 $2.52M SEC filing ↗
Aug 11, 2026 Albert Chao S Open-market sale 7,489 $79.70 $596.9K SEC filing ↗
Aug 11, 2026 Albert Chao M Option exercise or conversion 38,873 $61.87 $2.41M SEC filing ↗
Aug 8, 2026 Jeffrey Wayne Sheets M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 R. Bruce Northcutt M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 Kimberly S Lubel M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 Michael J Graff M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 Roger A. Cregg M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 David Tsung-Hung Chao M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
Aug 8, 2026 Catherine T Chao M Option exercise or conversion 2,168 $0.00 $0 SEC filing ↗
May 13, 2026 Mark Steven Bender F Shares withheld for taxes 5,284 $97.34 $514.3K SEC filing ↗
May 12, 2026 Mark Steven Bender M Option exercise or conversion 13,164 $0.00 $0 SEC filing ↗
Mar 27, 2026 Robert F Buesinger S Open-market sale 4,000 $115.25 $461.0K SEC filing ↗
Mar 27, 2026 Mark Steven Bender S Open-market sale 16,413 $112.54 $1.85M SEC filing ↗
Feb 27, 2026 Mark Steven Bender M Option exercise or conversion 6,494 $86.54 $562.0K SEC filing ↗
Feb 27, 2026 Mark Steven Bender D Disposition to the issuer 12,693 $98.20 $1.25M SEC filing ↗
Feb 27, 2026 Mark Steven Bender S Open-market sale 16,988 $100.91 $1.71M SEC filing ↗
Feb 27, 2026 Mark Steven Bender S Open-market sale 421 $101.52 $42.7K SEC filing ↗
Feb 27, 2026 Mark Steven Bender M Option exercise or conversion 6,199 $65.81 $408.0K SEC filing ↗
Feb 20, 2026 Scott Thomas Szwejbka F Shares withheld for taxes 91 $94.10 $8.6K SEC filing ↗
Feb 20, 2026 Robert F Buesinger F Shares withheld for taxes 326 $94.10 $30.7K SEC filing ↗
Feb 20, 2026 Mark Steven Bender F Shares withheld for taxes 445 $94.10 $41.9K SEC filing ↗
Feb 20, 2026 L. Benjamin Ederington F Shares withheld for taxes 357 $94.10 $33.6K SEC filing ↗
Feb 20, 2026 James Chao F Shares withheld for taxes 1,569 $94.10 $147.6K SEC filing ↗
Feb 20, 2026 Albert Chao F Shares withheld for taxes 2,501 $94.10 $235.3K SEC filing ↗

From SEC Form 4 filings. Every row links to the filing it came from. How we calculate this.

What a Form 4 is

The report an officer, director or large shareholder must file after trading their own company’s stock.

Subsidiaries — 40 legal entities

Subsidiaries of WESTLAKE CORP

40 legal entities named in the subsidiary exhibit filed with this company’s most recent 10-K. . Filing on SEC.gov.

This is not the full list. SEC rules only require a company to name its significant subsidiaries.

What that leaves out

Smaller entities are left out of the exhibit entirely. A short list here means a short exhibit — it does not mean the company owns nothing else. Nothing on this page is inferred: every name below is copied from the filing.

Subsidiaries WESTLAKE CORP names in its most recent annual report, with the place each one is organised.
Subsidiary Organised in
Eagle Spinco Inc. Delaware
Rome Delaware Corp. Delaware
Taiwan Chlorine Industries, Ltd. Kaohsiung, Taiwan
Westlake Canada Inc. Toronto, Canada
Westlake Chemical Canada Inc. Montreal, Canada
Westlake Chemical OpCo LP Delaware
Westlake Chemical Partners GP LLC Delaware
Westlake Chemical Partners LP Delaware
Westlake Chemicals & Vinyls LLC Delaware
Westlake Compounds LLC Delaware
Westlake DaVinci Roofscapes L.L.C. Delaware
Westlake Dimex LLC Delaware
Westlake Epoxy B.V. Rotterdam, The Netherlands
Westlake Epoxy GmbH Duisburg, Germany
Westlake Epoxy Inc. Delaware
Westlake Germany GmbH & Co. KG Ismaning, Germany
Westlake International I B.V. Rotterdam, The Netherlands
Westlake Longview Corporation Delaware
Westlake Management (Shanghai) Co. Ltd Shanghai, China
Westlake Management Services, Inc. Delaware
Westlake Natrium LLC Delaware
Westlake Petrochemicals LLC Delaware
Westlake Pipe & Fittings Corporation Delaware
Westlake Polymers LLC Delaware
Westlake Royal Building Products (USA) Inc. Delaware
Westlake Royal Building Products Inc. Delaware
Westlake Royal Roofing LLC Delaware
Westlake Royal Stone LLC Delaware
Westlake Royal Windows LLC Delaware
Westlake Styrene LLC Delaware
Westlake Switzerland GmbH Baas, Switzerland
Westlake US 2 LLC Delaware
Westlake Vinnolit GmbH & Co. KG Ismaning, Germany
Westlake Vinnolit Holdings GmbH —
Westlake Vinnolit Italia S.r.L. —
Westlake Vinnolit Limited —
Westlake Vinnolit Treuhand GmbH —
Westlake Vinyls Company LP —
Westlake Vinyls, Inc. —
WPT LLC —
What counts as a subsidiary

A subsidiary is a separate legal entity this company controls; it is not the same thing as a brand, a division or an office. These entities do not file with the SEC in their own right, so there is no separate page to open for them.

Think a number here is wrong? Open the linked filing and compare — how to report it.

Sources and technical notes

Every figure on this page comes from filings to the U.S. SEC via EDGAR. Nothing here is estimated, and nothing is taken from press coverage or company websites.

Share count: cover page of the latest filing (dei:EntityCommonStockSharesOutstanding), taken from WESTLAKE CORP’s own filings and multiplied by our closing price. Full method.

What that share count means

the share count the company itself prints on the cover of its most recent filing, as of the date it signed that filing.

We do not take a market cap from a data vendor, and we do not estimate one: the figure is a share count from WESTLAKE CORP’s own SEC filings multiplied by the closing price we hold for the same stock.

Logo: Unknown author / Public domain , via Wikimedia Commons ↗ — used here to identify the company. Trademarks remain the property of their owner.