| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Burke Kathleen Flaherty | EVP, GC & Secretary | C/O MKS INC., 2 TECH DRIVE, ANDOVER | /s/ M. Kathryn Rickards, attorney-in-fact | 23 Feb 2026 | 0001775435 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | MKSI | Common Stock | Sale | $1,063,500 | -4,254 | -7.3% | $250.00 | 53,794 | 20 Feb 2026 | Direct |