As of March 23, 2026, the three largest insider holders of WLK are Albert Chao (Executive Chairman, 642.88K shares), L. Benjamin Ederington (Evp, Legal External Affairs, 80.16K shares), Dorothy C Jenkins (Director, 73.78K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Albert Chao | Executive Chairman | 642,880 | 0 | 23 Feb, 2026 |
| L. Benjamin Ederington | Evp, Legal External Affairs | 80,158 | 0 | 23 Feb, 2026 |
| Dorothy C Jenkins | 73,778 | 0 | 15 Aug, 2022 | |
| James Chao | Senior Chairman | 49,774 | 0 | 23 Feb, 2026 |
| Mark Steven Bender | Evp Cfo | 44,433 | 0 | 02 Mar, 2026 |
| Roger L. Kearns | Coo And Evp, Pem | 39,849 | 0 | 15 Mar, 2023 |
| Robert F. Buesinger | Evp, Pem Segment Head | 38,482 | 0 | 23 Feb, 2026 |
| R Bruce Northcutt | 21,183 | 0 | 11 Aug, 2025 | |
| Michael J Graff | 21,142 | 0 | 11 Aug, 2025 | |
| Andrew Kenner | Svp, Operations | 20,362 | 0 | 22 Feb, 2022 |
| Catherine T. Chao | 0 | 19,423 | 01 Sep, 2023 | |
| David Tsung-Hung Chao | 0 | 19,423 | 01 Sep, 2023 | |
| Thomas J. Janssens | Svp, Ops Pem Corp Logistic | 17,127 | 0 | 24 Feb, 2025 |
| Scott Thomas Szwejbka | Svp, Hip Segment Head | 13,773 | 0 | 23 Feb, 2026 |
| Jeffrey Wayne Sheets | 12,759 | 0 | 11 Aug, 2025 | |
| Kimberly S Lubel | 11,653 | 0 | 11 Aug, 2025 | |
| Marius Haas | 11,631 | 0 | 12 Aug, 2024 | |
| David Tsung-Hung Chao | 8,912 | 0 | 11 Aug, 2025 | |
| John Tsung-Chen Chao | 7,888 | 0 | 23 Feb, 2026 | |
| Catherine T. Chao | 5,580 | 0 | 11 Aug, 2025 | |
| Jeffrey Adam Holy | Vp And Cao | 5,124 | 0 | 23 Feb, 2026 |
| Johnathan Stevan Zoeller | Vp And Cao | 4,416 | 0 | 22 Mar, 2024 |
| Carolyn Chao Sabat | 3,580 | 0 | 11 Aug, 2025 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 27 Feb, 2026 | Mark Steven Bender | Common Stock | A | 6,199 | $65.81 | 68,041 | D | M |
| 27 Feb, 2026 | Mark Steven Bender | Common Stock | A | 6,494 | $86.54 | 74,535 | D | M |
| 27 Feb, 2026 | Mark Steven Bender | Common Stock | D | 12,693 | $98.20 | 61,842 | D | D |
| 27 Feb, 2026 | Mark Steven Bender | Common Stock | D | 16,988 | $100.91 | 44,854 | D | S |
| 27 Feb, 2026 | Mark Steven Bender | Common Stock | D | 421 | $101.52 | 44,433 | D | S |
| 27 Feb, 2026 | Mark Steven Bender | Employee Option (right to buy) | D | 6,199 | $0.00 | 0 | D | M |
| 27 Feb, 2026 | Mark Steven Bender | Employee Option (right to buy) | D | 6,494 | $0.00 | 0 | D | M |
| 20 Feb, 2026 | Bhavesh V. Patel | Restricted Stock Units | A | 1,852 | $0.00 | 1,852 | D | A |
| 19 Feb, 2026 | John Tsung-Chen Chao | Common Stock | A | 213 | $0.00 | 7,979 | D | A |
| 19 Feb, 2026 | Mark Steven Bender | Common Stock | A | 1,777 | $0.00 | 62,287 | D | A |
| 19 Feb, 2026 | Jeffrey Adam Holy | Common Stock | A | 264 | $0.00 | 5,205 | D | A |
| 19 Feb, 2026 | James Chao | Common Stock | A | 3,884 | $0.00 | 51,343 | D | A |
| 19 Feb, 2026 | Scott Thomas Szwejbka | Common Stock | A | 365 | $0.00 | 13,864 | D | A |
| 19 Feb, 2026 | Robert F. Buesinger | Common Stock | A | 1,301 | $0.00 | 38,808 | D | A |
| 19 Feb, 2026 | L. Benjamin Ederington | Common Stock | A | 1,425 | $0.00 | 80,515 | D | A |
| 19 Feb, 2026 | Albert Chao | Common Stock | A | 6,193 | $0.00 | 645,381 | D | A |
| 20 Feb, 2026 | Jean-Marc Gilson | Employee Option (right to buy) | A | 109,139 | $0.00 | 109,139 | D | A |
| 20 Feb, 2026 | James Chao | Common Stock | D | 1,569 | $94.10 | 49,774 | D | F |
| 20 Feb, 2026 | Albert Chao | Common Stock | D | 2,501 | $94.10 | 642,880 | D | F |
| 20 Feb, 2026 | Robert F. Buesinger | Common Stock | D | 326 | $94.10 | 38,482 | D | F |