Westlake Corporation
Westlake Corporation (WLK) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · WLK · as of Sep 30, 2025
Ownership Breakdown
319
Institutional Holders
▼ 3 vs Q2
$3.20B
Total Inst. Value
▲ $206.72M vs Q2
128.12M
Shares Outstanding
freeFloat 25.95%
41.56M
13F Shares Held
▲ 2.14M vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
WLK largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
ORBIS ALLAN GRAY LTD industrial organic chemicals | 3.91M | 3.05% | 3.05% | $301.64B | Nov 14, 2025 | NEW |
VANGUARD GROUP INC industrial organic chemicals | 3.44M | 2.68% | 2.68% | $265.06B | Nov 7, 2025 | ▼ 83.2K |
BLACKROCK, INC. industrial organic chemicals | 3.19M | 2.48% | 2.48% | $245.49B | Nov 12, 2025 | ▼ 143.0K |
VICTORY CAPITAL MANAGEMENT INC industrial organic chemicals | 2.87M | 2.23% | 2.23% | $220.88B | Nov 12, 2025 | ▼ 855.4K |
PRICE T ROWE ASSOCIATES INC /MD/ industrial organic chemicals | 2.21M | 1.72% | 1.72% | $170.16B | Nov 14, 2025 | ▲ 149.6K |
BRANDES INVESTMENT PARTNERS, LP industrial organic chemicals | 1.55M | 1.21% | 1.21% | $119.34B | Nov 14, 2025 | ▲ 91.8K |
DIMENSIONAL FUND ADVISORS LP industrial organic chemicals | 1.30M | 1.01% | 1.01% | $100.20B | Nov 12, 2025 | ▲ 25.1K |
STATE STREET CORP industrial organic chemicals | 1.30M | 1.01% | 1.01% | $99.81B | Nov 14, 2025 | ▼ 97.0K |
CITADEL ADVISORS LLC industrial organic chemicals | 1.20M | 93.62% | 93.62% | $92.54B | Nov 14, 2025 | ▲ 1.19M |
GOLDMAN SACHS GROUP INC industrial organic chemicals | 1.05M | 81.97% | 81.97% | $81.02B | Nov 14, 2025 | ▼ 7.5K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
29
Increased
+4.66M shares5
New Positions
first time holders16
Decreased
−3.60M shares0
Sold Out
fully exitedNet shares change (top 50)
+1.06M
+4.66M / −3.60M
Net new holders
+18
5 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
WLK insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
2
Buy transactions
2
Sell transactions
1.00
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Bender Mark Steven EVP & CFO | May 13, 2026 | Tax Withhold | 5,284 | $97.34 | $514.3K | 35.9K | Form 4 ↗ |
Powers Brian John SVP, PEM Segment Head | Apr 2, 2026 | Award | 1,961 | — | — | 2.0K | Form 4 ↗ |
Buesinger Robert F. EVP, PEM Segment Head | Mar 27, 2026 | Sale | 4,000 | $115.25 | $461.0K | 34.5K | Form 4 ↗ |
Bender Mark Steven EVP & CFO | Mar 27, 2026 | Sale | 16,413 | $112.53 | $1.85M | 28.0K | Form 4 ↗ |
Bender Mark Steven EVP & CFO | Feb 16, 2022 | Tax Withhold | 1,171 | $104.96 | $122.9K | 25.6K | Form 4 ↗ |
Bender Mark Steven EVP & CFO | Feb 27, 2026 | D-Return | 12,693 | $98.20 | $1.25M | 61.8K | Form 4 ↗ |
Bender Mark Steven EVP & CFO | Feb 27, 2026 | Sale | 16,988 | $100.91 | $1.71M | 44.9K | Form 4 ↗ |
Bender Mark Steven EVP & CFO | Feb 27, 2026 | Sale | 421 | $101.52 | $42.7K | 44.4K | Form 4 ↗ |
Patel Bhavesh V. director | Feb 20, 2026 | Award | 1,852 | — | — | 1.9K | Form 4 ↗ |
Szwejbka Scott Thomas SVP, HIP Segment Head | Feb 20, 2026 | Award | 14,595 | $94.48 | $1.38M | 14.6K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Westlake Corporation (WLK) is primarily owned by institutional investors, who hold approximately 32.4% of total shares outstanding. Company insiders own approximately 74.05%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Westlake Corporation is ORBIS ALLAN GRAY LTD, holding approximately 3.91 million shares — equal to 3.05% of outstanding shares — as of September 30, 2025.
A total of 319 institutional investors currently hold WLK stock, with a combined institutional value of approximately $3.20 billion as of the most recent 13F filing period.
Frequently asked questions
WLK ownershipWestlake Corporation (WLK) is primarily owned by institutional investors, who hold approximately 32.4% of shares. The largest shareholder is ORBIS ALLAN GRAY LTD with a 3.05% stake. Company insiders hold 74.05%. Data sourced from SEC Form 13F as of September 30, 2025.