According to recent filings covering the 90 days ending January 13, 2026, the three most significant insider holders at Westlake are Executive Chairman Albert Chao (627.72K shares), Evp And Pem And Gc And Cao L. Benjamin Ederington (76.26K shares), Director Dorothy C Jenkins (73.78K shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Albert Chao | Executive Chairman | 627,722 | 23 Dec, 2025 |
| L. Benjamin Ederington | Evp And Pem And Gc And Cao | 76,259 | 24 Feb, 2025 |
| Dorothy C Jenkins | 73,778 | 15 Aug, 2022 | |
| Mark Steven Bender | Evp & Cfo | 56,968 | 24 Feb, 2025 |
| Roger L. Kearns | Coo And Evp And Pem | 39,849 | 15 Mar, 2023 |
| James Chao | Senior Chairman | 39,741 | 29 Aug, 2025 |
| Robert F. Buesinger | Evp And Hip And It & Digital | 34,932 | 24 Feb, 2025 |
| David Tsung-Hung Chao | 28,335 | 11 Aug, 2025 | |
| Catherine T. Chao | 25,003 | 11 Aug, 2025 | |
| R Bruce Northcutt | 21,183 | 11 Aug, 2025 | |
| Michael J Graff | 21,142 | 11 Aug, 2025 | |
| Andrew Kenner | Svp And Operations | 20,362 | 22 Feb, 2022 |
| Thomas J. Janssens | Svp And Ops Pem & Corp Logistic | 17,127 | 24 Feb, 2025 |
| Scott Thomas Szwejbka | Svp And Hip Segment Head | 12,817 | 03 Oct, 2025 |
| Jeffrey Wayne Sheets | 12,759 | 11 Aug, 2025 | |
| Kimberly S Lubel | 11,653 | 11 Aug, 2025 | |
| Marius Haas | 11,631 | 12 Aug, 2024 | |
| Mark A Mccollum | 9,656 | 11 Aug, 2025 | |
| John Tsung-Chen Chao | 7,038 | 07 Mar, 2025 | |
| Jeffrey Adam Holy | Vp And Cao | 4,448 | 24 Feb, 2025 |
| Johnathan Stevan Zoeller | Vp And Cao | 4,416 | 22 Mar, 2024 |
| Carolyn Chao Sabat | 3,580 | 11 Aug, 2025 | |
| Roger A Cregg | 1,339 | 10 Dec, 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 |
|---|---|---|---|---|---|---|---|---|
| 22 Dec, 2025 | Albert Chao | Common Stock | D | 521 | $74.44 | 627,722 | D | S |
| 22 Dec, 2025 | Albert Chao | Common Stock | A | 81,673 | $44.42 | 668,558 | D | M |
| 22 Dec, 2025 | Albert Chao | Common Stock | D | 9,711 | $72.82 | 658,847 | D | S |
| 22 Dec, 2025 | Albert Chao | Common Stock | D | 30,604 | $73.80 | 628,243 | D | S |
| 10 Dec, 2025 | Roger A Cregg | Common Stock | A | 1,339 | - | 1,339 | D | M |
| 02 Oct, 2025 | Scott Thomas Szwejbka | Common Stock | D | 3,842 | $76.70 | 12,817 | D | F |
| 01 Oct, 2025 | Scott Thomas Szwejbka | Common Stock | A | 10,840 | $0.00 | 16,659 | D | M |
| 28 Aug, 2025 | James Chao | - | - | 39,741 | D | |||
| 28 Aug, 2025 | James Chao | Common Stock | D | 15,140 | $0.00 | 39,741 | D | G |
| 09 Aug, 2025 | Mark A Mccollum | Common Stock | A | 1,128 | - | 9,656 | D | M |
| 09 Aug, 2025 | R Bruce Northcutt | Common Stock | A | 1,128 | - | 21,183 | D | M |
| 09 Aug, 2025 | Jeffrey Wayne Sheets | Common Stock | A | 1,128 | - | 12,759 | D | M |
| 09 Aug, 2025 | Kimberly S Lubel | Common Stock | A | 1,128 | - | 11,653 | D | M |
| 09 Aug, 2025 | Michael J Graff | Common Stock | A | 1,128 | - | 21,142 | D | M |
| 09 Aug, 2025 | David Tsung-Hung Chao | Common Stock | A | 1,128 | - | 8,912 | D | M |
| 09 Aug, 2025 | David Tsung-Hung Chao | - | - | 8,912 | D | |||
| 09 Aug, 2025 | Carolyn Chao Sabat | Common Stock | A | 1,128 | - | 3,580 | D | M |
| 09 Aug, 2025 | Catherine T. Chao | Common Stock | A | 1,128 | - | 5,580 | D | M |
| 27 May, 2025 | Robert F. Buesinger | - | - | 0 | I | |||
| 27 May, 2025 | Robert F. Buesinger | Common Stock | D | 83 | $72.70 | 0 | I | S |