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 Mar 31, 2025
Ownership Breakdown
369
Institutional Holders
▼ 20 vs Q4
$3.64B
Total Inst. Value
▼ $389.15M vs Q4
128.12M
Shares Outstanding
freeFloat 25.95%
36.44M
13F Shares Held
▲ 1.19M vs Q4
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
Q1 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
VICTORY CAPITAL MANAGEMENT INC industrial organic chemicals | 3.90M | 3.04% | 3.04% | $390.12B | May 2, 2025 | ▲ 586.2K |
BLACKROCK, INC. industrial organic chemicals | 3.66M | 2.85% | 2.85% | $366.15B | May 2, 2025 | ▲ 2.5K |
VANGUARD GROUP INC industrial organic chemicals | 3.55M | 2.77% | 2.77% | $355.14B | May 9, 2025 | ▼ 327.7K |
STATE STREET CORP industrial organic chemicals | 1.63M | 1.27% | 1.27% | $163.06B | May 15, 2025 | ▲ 435.9K |
FMR LLC industrial organic chemicals | 1.55M | 1.21% | 1.21% | $154.93B | May 12, 2025 | ▲ 110.3K |
CAPITAL WORLD INVESTORS industrial organic chemicals | 1.29M | 1.01% | 1.01% | $129.05B | May 12, 2025 | ▲ 2.6K |
GOLDMAN SACHS GROUP INC industrial organic chemicals | 1.04M | 81.15% | 81.15% | $104.15B | Jun 27, 2025 | ▲ 102.3K |
DIMENSIONAL FUND ADVISORS LP industrial organic chemicals | 939.7K | 73.24% | 73.24% | $93.98B | May 13, 2025 | ▲ 5.5K |
MILLENNIUM MANAGEMENT LLC industrial organic chemicals | 901.2K | 70.24% | 70.24% | $90.15B | May 15, 2025 | ▲ 708.1K |
MIRAE ASSET GLOBAL ETFS HOLDINGS LTD. industrial organic chemicals | 853.8K | 66.55% | 66.55% | $85.41B | May 15, 2025 | ▼ 28.6K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q1 2025 vs prior quarter
Q1 2025
34
Increased
+4.05M shares2
New Positions
first time holders14
Decreased
−2.05M shares0
Sold Out
fully exitedNet shares change (top 50)
+2.00M
+4.05M / −2.05M
Net new holders
+22
2 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 28.4% 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 VICTORY CAPITAL MANAGEMENT INC, holding approximately 3.90 million shares — equal to 3.04% of outstanding shares — as of March 31, 2025.
A total of 369 institutional investors currently hold WLK stock, with a combined institutional value of approximately $3.64 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 28.4% of shares. The largest shareholder is VICTORY CAPITAL MANAGEMENT INC with a 3.04% stake. Company insiders hold 74.05%. Data sourced from SEC Form 13F as of March 31, 2025.