According to recent filings covering the 90 days ending December 20, 2025, the three most significant insider holders at Mks are President & CEO John Tseng-Chung Lee (147.27K shares), EVP And GC & Secretary Kathleen Flaherty Burke (51.07K shares), EVP & COO James Alan Schreiner (22.53K shares).
| Holder | Position | Shares | Report Date |
|---|---|---|---|
| Group Inc. Carlyle | 6,482,732 | 10 May, 2023 | |
| Partners Vi Cayman Holdings, L.P. Carlyle | 6,482,732 | 10 May, 2023 | |
| John Tseng-Chung Lee | President & CEO | 147,270 | 04 Nov, 2025 |
| Gerard G Colella | 68,234 | 13 May, 2025 | |
| Kathleen Flaherty Burke | EVP And GC & Secretary | 51,075 | 04 Nov, 2025 |
| James Alan Schreiner | EVP & COO | 22,535 | 23 Oct, 2025 |
| Elizabeth Mora | 18,963 | 03 Dec, 2025 | |
| Eric Robert Taranto | EVP & GM And Vsd | 17,467 | 19 Feb, 2025 |
| Mark Milton Gitin | EVP & GM And Psd | 16,134 | 16 Feb, 2024 |
| David Philip Henry | EVP And Global Str Mktg & GM And Msd | 15,571 | 19 Sep, 2025 |
| Raj Batra | 15,445 | 13 May, 2025 | |
| Jacqueline F Moloney | 11,562 | 02 Oct, 2025 | |
| Joseph B Donahue | 11,351 | 13 May, 2025 | |
| Michelle M Warner | 10,852 | 08 May, 2024 | |
| Peter Iii Cannone | 9,612 | 13 May, 2025 | |
| Ramakumar Mayampurath | EVP & Cfo | 5,667 | 18 Nov, 2025 |
| Wissam G Jabre | 4,488 | 13 May, 2025 | |
| John Edward Williams | EVP & GM And Psd | 3,640 | 18 Aug, 2025 |
| Geoffrey Wild | 1,813 | 18 Aug, 2022 | |
| Michelle M Mccarthy | VP & Chief Accounting Officer | 1,466 | 17 Apr, 2025 |
| Seth H Bagshaw | EVP And CFO & Treasurer | 1 | 26 Feb, 2024 |
* 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 |
|---|---|---|---|---|---|---|---|---|
| 02 Dec, 2025 | Elizabeth Mora | Common Stock | D | 300 | $158.81 | 18,963 | D | S |
| 17 Nov, 2025 | Ramakumar Mayampurath | Common Stock | A | 8,295 | - | 8,295 | D | M |
| 17 Nov, 2025 | Ramakumar Mayampurath | Common Stock | D | 2,628 | $142.74 | 5,667 | D | F |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | A | 158 | - | 51,233 | D | M |
| 31 Oct, 2025 | John Tseng-Chung Lee | Common Stock | A | 352 | - | 147,622 | D | M |
| 31 Oct, 2025 | John Tseng-Chung Lee | Common Stock | A | 1,651 | - | 149,273 | D | M |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | A | 52 | - | 51,285 | D | M |
| 31 Oct, 2025 | John Tseng-Chung Lee | Common Stock | D | 2,003 | $143.71 | 147,270 | D | F |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | A | 82 | - | 51,367 | D | M |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | A | 144 | - | 51,511 | D | M |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | A | 341 | - | 51,852 | D | M |
| 31 Oct, 2025 | Kathleen Flaherty Burke | Common Stock | D | 777 | $143.71 | 51,075 | D | F |
| 22 Oct, 2025 | James Alan Schreiner | Common Stock | D | 711 | $138.68 | 22,535 | D | S |
| 01 Oct, 2025 | Jacqueline F Moloney | Common Stock | D | 300 | $122.14 | 11,562 | D | S |
| 18 Sep, 2025 | James Alan Schreiner | Common Stock | D | 838 | $124.00 | 23,246 | D | S |
| 18 Sep, 2025 | David Philip Henry | Common Stock | D | 5,000 | $130.00 | 15,571 | D | S |
| 18 Sep, 2025 | David Philip Henry | - | - | 15,571 | D | |||
| 02 Sep, 2025 | Elizabeth Mora | Common Stock | D | 300 | $99.85 | 19,263 | D | S |
| 18 Aug, 2025 | James Alan Schreiner | Common Stock | A | 2,641 | - | 25,333 | D | M |
| 18 Aug, 2025 | James Alan Schreiner | Common Stock | D | 1,249 | $100.22 | 24,084 | D | F |