As of June 06, 2026, the three largest insider holders of MKSI are Partners Vi Cayman Holdings, L.P. Carlyle (TenPercentOwner, 6.48Mn shares), Group Inc. Carlyle (TenPercentOwner, 6.48Mn shares), John Tseng-Chung Lee (President Ceo, 154.70K shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Seth H Bagshaw | Evp, Cfo Treasurer | 1 | 0 | 26 Feb, 2024 |
| Gerard G Colella | Ceo, Director | 0 | 68,017 | 12 Feb, 2024 |
| Peter Iii Cannone | - | 8,362 | 0 | 23 Feb, 2026 |
| Geoffrey Wild | - | 1,813 | 0 | 18 Aug, 2022 |
| Joseph B Donahue | - | 11,351 | 0 | 13 May, 2025 |
| John Tseng-Chung Lee | President Ceo | 154,696 | 0 | 23 Feb, 2026 |
| Jacqueline F Moloney | - | 10,393 | 0 | 13 Mar, 2026 |
| Group Inc. Carlyle | - | 0 | 6,482,732 | 10 May, 2023 |
| Michelle M Warner | - | 10,852 | 0 | 08 May, 2024 |
| John Edward Williams | Evp Gm, Psd | 4,555 | 0 | 20 Apr, 2026 |
| Michelle M Mccarthy | Svp Chief Accounting Officer | 2,436 | 0 | 16 Apr, 2026 |
| Raj Batra | - | 15,445 | 0 | 13 May, 2025 |
| Kathleen Flaherty Burke | Evp, Gc Secretary | 53,794 | 0 | 23 Feb, 2026 |
| James Alan Schreiner | Evp Coo | 23,402 | 0 | 25 Feb, 2026 |
| Partners Vi Cayman Holdings, L.P. Carlyle | - | 0 | 6,482,732 | 10 May, 2023 |
| Eric Robert Taranto | Evp Gm, Vsd | 15,445 | 0 | 09 Mar, 2026 |
| David Philip Henry | Evp, Global Str Mktg Gm, Msd | 18,841 | 0 | 23 Feb, 2026 |
| Mark Milton Gitin | Evp Gm, Psd | 16,134 | 0 | 16 Feb, 2024 |
| Ramakumar Mayampurath | Evp Cfo | 8,811 | 0 | 18 Feb, 2026 |
| Wissam G Jabre | - | 4,488 | 0 | 13 May, 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 |
|---|---|---|---|---|---|---|---|---|
| 17 Apr, 2026 | John Edward Williams | Common Stock | A | 1,741 | - | 5,381 | D | M |
| 17 Apr, 2026 | John Edward Williams | Common Stock | D | 826 | $269.89 | 4,555 | D | F |
| 17 Apr, 2026 | John Edward Williams | Restricted Stock Unit | D | 1,741 | - | 6,812 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 968 | - | 968 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 968 | - | 968 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 968 | - | 968 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,107 | - | 2,075 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,107 | - | 2,075 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,107 | - | 2,075 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,736 | - | 3,811 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,736 | - | 3,811 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | A | 1,736 | - | 3,811 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | D | 1,375 | $274.15 | 2,436 | D | F |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | D | 1,375 | $274.15 | 2,436 | D | F |
| 15 Apr, 2026 | Michelle M Mccarthy | Common Stock | D | 1,375 | $274.15 | 2,436 | D | F |
| 15 Apr, 2026 | Michelle M Mccarthy | Restricted Stock Unit | A | 1,673 | - | 11,199 | D | A |
| 15 Apr, 2026 | Michelle M Mccarthy | Restricted Stock Unit | A | 1,673 | - | 11,199 | D | A |
| 15 Apr, 2026 | Michelle M Mccarthy | Restricted Stock Unit | A | 1,673 | - | 11,199 | D | A |
| 15 Apr, 2026 | Michelle M Mccarthy | Restricted Stock Unit | D | 968 | - | 10,231 | D | M |
| 15 Apr, 2026 | Michelle M Mccarthy | Restricted Stock Unit | D | 968 | - | 10,231 | D | M |