| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Schreiner James Alan | EVP & COO | C/O MKS INC., 2 TECH DRIVE, ANDOVER | /s/ M. Kathryn Rickards, attorney-in-fact | 25 Feb 2026 | 0001797189 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | MKSI | Common Stock | Sale | $1,045,500 | -4,100 | -15% | $255.00 | 23,402 | 24 Feb 2026 | Direct |