WLK · Insider Trading
Westlake Corporation
Every open-market purchase and sale reported by WLK officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-09-01 | Tommy Darby | VP and CAO | A | +1,791 deriv. | — |
| 2026-08-17 | Mark A McCollum | Director | A | +2,184 deriv. | — |
| 2026-08-17 | David Tsung-Hung Chao | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Bhavesh V. Patel | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Carolyn Chao Sabat | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Roger A Cregg | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Michael J Graff | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Kimberly S Lubel | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Jeffrey Wayne Sheets | Director | A | +2,184 deriv. | — |
| 2026-08-17 | Catherine T. Chao | Director | A | +2,184 deriv. | — |
| 2026-08-17 | R Bruce Northcutt | Director | A | +2,184 deriv. | — |
| 2026-08-11 | Albert Chao | Executive Chairman | MIXED | — | −$715.90K |
| 2026-08-10 | Carolyn Chao Sabat | Director | M | +2,168 | — |
| 2026-08-10 | Michael J Graff | Director | M | +2,168 | — |
| 2026-08-10 | David Tsung-Hung Chao | Director | M | +2,168 | — |
| 2026-08-10 | Roger A Cregg | Director | M | +2,168 | — |
| 2026-08-10 | Kimberly S Lubel | Director | M | +2,168 | — |
| 2026-08-10 | Jeffrey Wayne Sheets | Director | M | +2,168 | — |
| 2026-08-10 | Catherine T. Chao | Director | M | +2,168 | — |
| 2026-08-10 | Mark A McCollum | Director | M | +2,168 | — |
| 2026-08-10 | R Bruce Northcutt | Director | M | +2,168 | — |
| 2026-06-16 | Jonathan Baksht | SVP and CFO | A | +20,580 deriv. | — |
| 2026-05-14 | Mark Steven Bender | EVP & CFO | MIXED | +7,880 | −$514.34K |
| 2026-04-06 | Brian John Powers | SVP, PEM Segment Head | A | +1,961 deriv. | — |
| 2026-03-31 | Robert F. Buesinger | EVP, PEM Segment Head | Sell | −4,000 | −$461.00K |
| 2026-03-30 | Mark Steven Bender | EVP & CFO | Sell | −16,413 | −$1.85M |
| 2026-03-06 | Mark Steven Bender | EVP & CFO | F | −1,171 | −$122.91K |
| 2026-03-02 | Mark Steven Bender | EVP & CFO | MIXED | −17,409 | −$2.03M |
| 2026-02-24 | Bhavesh V. Patel | Director | A | +1,852 deriv. | — |
| 2026-02-23 | James Chao | Senior Chairman | MIXED | +2,315 | −$147.64K |
| 2026-02-23 | Albert Chao | Executive Chairman | MIXED | +3,692 | −$235.35K |
| 2026-02-23 | John Tsung-chen Chao | Director | MIXED | +122 | −$8.56K |
| 2026-02-23 | Mark Steven Bender | EVP & CFO | MIXED | +1,332 | −$41.87K |
| 2026-02-23 | Robert F. Buesinger | EVP, PEM Segment Head | MIXED | +975 | −$30.68K |
| 2026-02-23 | L. Benjamin Ederington | EVP, Legal & External Affairs | MIXED | +1,068 | −$33.59K |
| 2026-02-23 | Jean-Marc Gilson | President and CEO | A | +138,923 deriv. | — |
| 2026-02-23 | Jeffrey Adam Holy | VP and CAO | MIXED | +183 | −$7.62K |
| 2026-02-23 | Scott Thomas Szwejbka | SVP, HIP Segment Head | MIXED | +274 | −$8.56K |
| 2026-02-19 | Mark Steven Bender | EVP & CFO | MIXED | +3,542 | −$119.63K |
| 2026-02-19 | Robert F. Buesinger | EVP, PEM Segment Head | MIXED | +2,575 | −$89.35K |
| 2026-02-19 | Albert Chao | Executive Chairman | MIXED | +11,466 | −$503.56K |
| 2026-02-19 | John Tsung-chen Chao | Director | MIXED | +328 | −$23.95K |
| 2026-02-19 | James Chao | Senior Chairman | MIXED | +7,718 | −$263.60K |
| 2026-02-19 | L. Benjamin Ederington | EVP, Legal & External Affairs | MIXED | +2,831 | −$96.77K |
| 2026-02-19 | Jeffrey Adam Holy | VP and CAO | MIXED | +493 | −$21.08K |
| 2026-02-19 | Scott Thomas Szwejbka | SVP, HIP Segment Head | MIXED | +682 | −$29.19K |
| 2025-12-23 | Albert Chao | Executive Chairman | MIXED | +40,837 | +$623.54K |
| 2025-12-10 | Roger A Cregg | Director | M | +1,339 | — |
| 2025-10-03 | Scott Thomas Szwejbka | SVP, HIP Segment Head | MIXED | +6,998 | −$294.68K |
| 2025-08-29 | James Chao | Senior Chairman | G | −15,140 | — |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| Albert Chao | Executive Chairman | 94,079,818 | $5.96B |
| James Chao | Senior Chairman | 93,455,328 | $5.92B |
| John Tsung-chen Chao | Director | 93,413,442 | $5.92B |
| Carolyn Chao Sabat | Director | 93,411,302 | $5.92B |
| L. Benjamin Ederington | EVP, Legal & External Affairs | 80,515 | $5.10M |
| Mark Steven Bender | EVP & CFO | 35,895 | $2.27M |
| Robert F. Buesinger | EVP, PEM Segment Head | 34,482 | $2.18M |
| David Tsung-Hung Chao | Director | 30,503 | $1.93M |
| Catherine T. Chao | Director | 27,171 | $1.72M |
| R Bruce Northcutt | Director | 23,351 | $1.48M |
| Michael J Graff | Director | 23,310 | $1.48M |
| Thomas J. Janssens | SVP, Ops - PEM & Corp Logistic | 17,733 | $1.12M |
| Jeffrey Wayne Sheets | Director | 14,927 | $945.33K |
| Kimberly S Lubel | Director | 13,821 | $875.28K |
| Scott Thomas Szwejbka | SVP, HIP Segment Head | 13,773 | $872.24K |
| Mark A McCollum | Director | 11,824 | $748.81K |
| Jeffrey Adam Holy | VP and CAO | 5,124 | $324.50K |
| Roger A Cregg | Director | 3,507 | $222.10K |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the WLK quote page; the site-wide leaderboard is on the insider transactions hub.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.