John Tseng-Chung Lee - 17 Feb 2026 Form 4 Insider Report for MKS INC (MKSI)

Role
President & CEO, Director
Signature
/s/ M. Kathryn Rickards, attorney-in-fact
Issuer symbol
MKSI
Transactions as of
17 Feb 2026
Net transactions value
-$8,486,646
Form type
4
Filing time
18 Feb 2026, 16:52:34 UTC
Previous filing
09 Feb 2026
Next filing
23 Feb 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Lee John Tseng-Chung President & CEO, Director C/O MKS INC., 2 TECH DRIVE, ANDOVER /s/ M. Kathryn Rickards, attorney-in-fact 18 Feb 2026 0001414656

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction MKSI Common Stock Options Exercise +22,088 +15% 169,443 17 Feb 2026 Direct F1
transaction MKSI Common Stock Options Exercise +7,654 +4.5% 177,097 17 Feb 2026 Direct F1
transaction MKSI Common Stock Options Exercise +3,859 +2.2% 180,956 17 Feb 2026 Direct F1
transaction MKSI Common Stock Options Exercise +7,208 +4% 188,164 17 Feb 2026 Direct F1
transaction MKSI Common Stock Options Exercise +16,989 +9% 205,153 17 Feb 2026 Direct F1
transaction MKSI Common Stock Options Exercise +12,091 +5.9% 217,244 17 Feb 2026 Direct F1
transaction MKSI Common Stock Tax liability $8,486,646 -32,548 -15% $260.74 184,696 17 Feb 2026 Direct F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction MKSI Restricted Stock Unit Award +15,593 +11% 154,717 17 Feb 2026 Common Stock 15,593 Direct F1, F3
transaction MKSI Restricted Stock Unit Options Exercise -22,088 -14% 132,629 17 Feb 2026 Common Stock 22,088 Direct F1, F4
transaction MKSI Restricted Stock Unit Options Exercise -7,654 -5.8% 124,976 17 Feb 2026 Common Stock 7,654 Direct F1, F5
transaction MKSI Restricted Stock Unit Options Exercise -3,859 -3.1% 121,117 17 Feb 2026 Common Stock 3,859 Direct F1, F6
transaction MKSI Restricted Stock Unit Options Exercise -7,208 -6% 113,909 17 Feb 2026 Common Stock 7,208 Direct F1, F7
transaction MKSI Restricted Stock Unit Options Exercise -16,989 -15% 96,919 17 Feb 2026 Common Stock 16,989 Direct F1, F8
transaction MKSI Restricted Stock Unit Options Exercise -12,091 -12% 84,828 17 Feb 2026 Common Stock 12,091 Direct F1, F9
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.
F2 These shares were withheld by MKS Inc. to satisfy the tax withholding obligations triggered by the vesting of RSUs and do not represent a discretionary trade by the reporting person.
F3 These RSUs vest in three equal annual installments commencing on February 15, 2027, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F4 These RSUs were subject to performance criteria, the achievement of which was determined on February 5, 2024, and thereafter vest in three equal annual installments beginning on February 15, 2024, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F5 These RSUs vest in three equal annual installments commencing on February 15, 2024, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F6 These RSUs were subject to performance criteria, the achievement of which was determined on February 10, 2025, and thereafter vest in three equal annual installments beginning on February 15, 2025, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F7 These RSUs vest in three equal annual installments commencing on February 15, 2025, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F8 These RSUs were subject to performance criteria, the achievement of which was determined on February 8, 2026, and thereafter vest in three equal annual installments beginning on February 15, 2026, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F9 These RSUs vest in three equal annual installments commencing on February 15, 2026, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.