MKSI

SEC source: 0001049502-26-000024 · form4.xml · nonDerivative · entry 5

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 29,901.726

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000024 · form4.xml · nonDerivative · entry 4

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,160.926

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000024 · form4.xml · nonDerivative · entry 3

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,949.926

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000024 · form4.xml · nonDerivative · entry 2

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,517.446

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000024 · form4.xml · nonDerivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,187.012

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000022 · form4.xml · derivative · entry 10

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,552.717

Underlying: Common Stock · 1,106 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F7 · derivative.exercise_date: 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.

F7 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000022 · form4.xml · derivative · entry 9

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,658.717

Underlying: Common Stock · 990.72 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F6 · derivative.exercise_date: 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.

F6 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000022 · form4.xml · derivative · entry 8

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,649.437

Underlying: Common Stock · 841 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F5 · derivative.exercise_date: 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.

F5 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000022 · form4.xml · derivative · entry 7

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,490.437

Underlying: Common Stock · 300.39 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F4 · derivative.exercise_date: 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.

F4 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000022 · form4.xml · derivative · entry 6

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,790.827

Underlying: Common Stock · 1,473.72 shares

Expires not disclosed

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F3 · derivative.exercise_date: 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.

F3 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000022 · form4.xml · nonDerivative · entry 5

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,682.724

F2 · kind: 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.

SEC source: 0001049502-26-000022 · form4.xml · nonDerivative · entry 4

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,878.209

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000022 · form4.xml · nonDerivative · entry 3

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,772.209

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000022 · form4.xml · nonDerivative · entry 2

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,781.489

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000022 · form4.xml · nonDerivative · entry 1

Williams John Edward · CIK 0001710173 · EVP & GM, PSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,940.489

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000020 · form4.xml · derivative · entry 6

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 23,898.453

Underlying: Common Stock · 2,702 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F5 · derivative.exercise_date: 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.

F5 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000020 · form4.xml · derivative · entry 5

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 26,600.453

Underlying: Common Stock · 2,958.08 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F4 · derivative.exercise_date: 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.

F4 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000020 · form4.xml · derivative · entry 4

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 29,558.533

Underlying: Common Stock · 4,278.543 shares

Expires not disclosed

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F3 · derivative.exercise_date: 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.

F3 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000020 · form4.xml · nonDerivative · entry 3

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,811.139

F2 · kind: 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.

SEC source: 0001049502-26-000020 · form4.xml · nonDerivative · entry 2

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,327.08

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000020 · form4.xml · nonDerivative · entry 1

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,625.08

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 14

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 84,828.121

Underlying: Common Stock · 12,091 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F9 · derivative.exercise_date: 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.

F9 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 13

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 96,919.121

Underlying: Common Stock · 16,989.44 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F8 · derivative.exercise_date: 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.

F8 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 12

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 113,908.561

Underlying: Common Stock · 7,208 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F7 · derivative.exercise_date: 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.

F7 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 11

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 121,116.561

Underlying: Common Stock · 3,859.12 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F6 · derivative.exercise_date: 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.

F6 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 10

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 124,975.681

Underlying: Common Stock · 7,653.601 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F5 · derivative.exercise_date: 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.

F5 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 9

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 132,629.282

Underlying: Common Stock · 22,088.091 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F4 · derivative.exercise_date: 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.

F4 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · derivative · entry 8

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 154,717.373

Underlying: Common Stock · 15,592.911 shares

Expires not disclosed

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F3 · derivative.exercise_date: 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.

F3 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 7

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 184,696.1077

F2 · kind: 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.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 6

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 217,244.4147

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 5

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 205,153.4147

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 4

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 188,163.9747

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 3

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 180,955.9747

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 2

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 177,096.8547

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000016 · form4.xml · nonDerivative · entry 1

Lee John Tseng-Chung · CIK 0001414656 · Director · President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 169,443.2537

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 14

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,128.986

Underlying: Common Stock · 2,493 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F9 · derivative.exercise_date: 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.

F9 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 13

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,621.986

Underlying: Common Stock · 2,336 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F8 · derivative.exercise_date: 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.

F8 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 12

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,957.986

Underlying: Common Stock · 1,576 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F7 · derivative.exercise_date: 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.

F7 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 11

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,533.986

Underlying: Common Stock · 562.54 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F6 · derivative.exercise_date: 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.

F6 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 10

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 22,096.526

Underlying: Common Stock · 1,787.735 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F5 · derivative.exercise_date: 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.

F5 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 9

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 23,884.261

Underlying: Common Stock · 3,450.859 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F4 · derivative.exercise_date: 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.

F4 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · derivative · entry 8

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,335.12

Underlying: Common Stock · 3,327.755 shares

Expires not disclosed

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F3 · derivative.exercise_date: 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.

F3 · derivative.expiration_date: 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.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 7

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 58,048.485

F2 · kind: 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.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 6

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 63,366.283

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 5

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 60,873.283

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 4

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 58,537.283

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 3

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,961.283

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 2

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 56,398.743

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000018 · form4.xml · nonDerivative · entry 1

Burke Kathleen Flaherty · CIK 0001775435 · EVP, GC & Secretary

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 54,611.008

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

SEC source: 0001049502-26-000014 · form4.xml · derivative · entry 1

Taranto Eric Robert · CIK 0001842235 · EVP & GM, VSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 12,742.601

Underlying: Common Stock · 3,504.314 shares

Expires not disclosed

F1 · derivative.exercise_price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F1 · price: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F2 · derivative.exercise_date: 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.

F2 · derivative.expiration_date: 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.