MKSI

SEC source: 0001049502-26-000012 · form4.xml · derivative · entry 1

Henry David Philip · CIK 0001842459 · EVP, Global Str Mktg & GM, MSD

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,808.107

Underlying: Common Stock · 5,521.949 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.

SEC source: 0001049502-26-000010 · form4.xml · derivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,244.899

Underlying: Common Stock · 5,226.759 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.

SEC source: 0001049502-26-000008 · form4.xml · derivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,317.107

Underlying: Common Stock · 2,973.357 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.

SEC source: 0001049502-26-000006 · form4.xml · derivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 24,007.365

Underlying: Common Stock · 7,008.628 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.

SEC source: 0001049502-26-000004 · form4.xml · derivative · entry 1

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,279.99

Underlying: Common Stock · 8,877.596 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.

SEC source: 0001049502-26-000002 · form4.xml · derivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 139,124.462

Underlying: Common Stock · 50,971.84 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.

SEC source: 0001049502-25-000041 · form4.xml · nonDerivative · entry 1

Mora Elizabeth · CIK 0001548935 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 18,963.394

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 19, 2025.

SEC source: 0001049502-25-000039 · form4.xml · derivative · entry 3

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 16,402.394

Underlying: Common Stock · 8,295 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.

F3 · derivative.exercise_date: These RSUs vest in two equal annual installments commencing on November 15, 2025, provided that if, in any vesting year, November 15th is not a business day, such vesting shall occur on the next business day.

F3 · derivative.expiration_date: These RSUs vest in two equal annual installments commencing on November 15, 2025, provided that if, in any vesting year, November 15th is not a business day, such vesting shall occur on the next business day.

SEC source: 0001049502-25-000039 · form4.xml · nonDerivative · entry 2

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,667

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: 0001049502-25-000039 · form4.xml · nonDerivative · entry 1

Mayampurath Ramakumar · CIK 0001859332 · EVP & CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,295

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: 0001049502-25-000037 · form4.xml · derivative · entry 11

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 16,998.737

Underlying: Common Stock · 341 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: Portion of 2025 RSU Award accelerated to satisfy FICA taxes.

F5 · derivative.expiration_date: Portion of 2025 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · derivative · entry 10

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,339.737

Underlying: Common Stock · 144 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: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

F4 · derivative.expiration_date: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · derivative · entry 9

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,483.737

Underlying: Common Stock · 82 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.

F3 · derivative.exercise_date: Portion of 2023 RSU Award accelerated to satisfy FICA taxes.

F3 · derivative.expiration_date: Portion of 2023 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · derivative · entry 8

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,565.737

Underlying: Common Stock · 52 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: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

F4 · derivative.expiration_date: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · derivative · entry 7

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 17,617.737

Underlying: Common Stock · 158 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.

F3 · derivative.exercise_date: Portion of 2023 RSU Award accelerated to satisfy FICA taxes.

F3 · derivative.expiration_date: Portion of 2023 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · nonDerivative · entry 6

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,074.509

F2 · kind: Shares used to satisfy FICA taxes.

SEC source: 0001049502-25-000037 · form4.xml · nonDerivative · entry 5

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,851.509

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: 0001049502-25-000037 · form4.xml · nonDerivative · entry 4

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,510.509

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: 0001049502-25-000037 · form4.xml · nonDerivative · entry 3

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,366.509

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: 0001049502-25-000037 · form4.xml · nonDerivative · entry 2

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,284.509

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: 0001049502-25-000037 · form4.xml · nonDerivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 51,232.509

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: 0001049502-25-000035 · form4.xml · derivative · entry 5

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 88,152.622

Underlying: Common Stock · 1,651 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: Portion of 2025 RSU Award accelerated to satisfy FICA taxes.

F4 · derivative.expiration_date: Portion of 2025 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000035 · form4.xml · derivative · entry 4

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 89,803.622

Underlying: Common Stock · 352 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.

F3 · derivative.exercise_date: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

F3 · derivative.expiration_date: Portion of 2024 RSU Award accelerated to satisfy FICA taxes.

SEC source: 0001049502-25-000035 · 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: 147,269.5227

F2 · kind: Shares used to satisfy FICA taxes.

SEC source: 0001049502-25-000035 · 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: 149,272.5227

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: 0001049502-25-000035 · 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: 147,621.5227

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: 0001049502-25-000033 · form4.xml · nonDerivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 22,534.694

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

SEC source: 0001049502-25-000031 · form4.xml · nonDerivative · entry 1

Moloney Jacqueline F · CIK 0001501968 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 11,562.304

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 10, 2024.

SEC source: 0001049502-25-000029 · form4.xml · nonDerivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 23,245.694

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

SEC source: 0001049502-25-000027 · form4.xml · nonDerivative · entry 1

Henry David Philip · CIK 0001842459 · EVP, Global Str Mktg & GM, MSD

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 15,571.18

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

SEC source: 0001049502-25-000025 · form4.xml · nonDerivative · entry 1

Mora Elizabeth · CIK 0001548935 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 19,263.394

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 19, 2025.

SEC source: 0001049502-25-000023 · form4.xml · derivative · entry 3

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,018.14

Underlying: Common Stock · 2,640.942 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.

F3 · derivative.exercise_date: These RSUs vest in two installments, 60% of which shall vest on August 17, 2024 and 40% of which shall vest on August 17, 2025; provided that if, in any vesting year, August 17th is not a business day, such vesting shall occur on the next business day.

F3 · derivative.expiration_date: These RSUs vest in two installments, 60% of which shall vest on August 17, 2024 and 40% of which shall vest on August 17, 2025; provided that if, in any vesting year, August 17th is not a business day, such vesting shall occur on the next business day.

SEC source: 0001049502-25-000023 · form4.xml · nonDerivative · entry 2

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 24,083.694

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: 0001049502-25-000023 · form4.xml · nonDerivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,332.694

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: 0001049502-25-000021 · form4.xml · derivative · entry 3

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 7,343.75

Underlying: Common Stock · 947.285 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.

F3 · derivative.exercise_date: These RSUs vest in two equal annual installments commencing on August 15, 2024, provided that if, in any vesting year, August 15th is not a business day, such vesting shall occur on the next business day.

F3 · derivative.expiration_date: These RSUs vest in two equal annual installments commencing on August 15, 2024, provided that if, in any vesting year, August 15th is not a business day, such vesting shall occur on the next business day.

SEC source: 0001049502-25-000021 · form4.xml · nonDerivative · entry 2

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,640.099

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: 0001049502-25-000021 · form4.xml · nonDerivative · entry 1

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 3,948.099

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: 0001049502-25-000019 · form4.xml · derivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,659.082

Underlying: Common Stock · 1,329.787 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 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.

F2 · 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: 0001049502-25-000016 · form4.xml · nonDerivative · entry 1

Moloney Jacqueline F · CIK 0001501968 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 11,862.304

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 10, 2024.

SEC source: 0001049502-25-000006 · form4.xml · nonDerivative · entry 1

Schreiner James Alan · CIK 0001797189 · EVP & COO, MSD

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 22,691.752

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

SEC source: 0001127602-25-018975 · form4.xml · nonDerivative · entry 1

Henry David Philip · CIK 0001842459 · EVP, Operations & Corp Mktg

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 20,571.18

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

SEC source: 0001127602-25-016398 · form4.xml · nonDerivative · entry 1

Mora Elizabeth · CIK 0001548935 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 19,563.394

F1 · kind: This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 19, 2025.

SEC source: 0001127602-25-014108 · form4.xml · nonDerivative · entry 1

Mora Elizabeth · CIK 0001548935 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,863.394

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014103 · form4.xml · nonDerivative · entry 1

Moloney Jacqueline F · CIK 0001501968 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 12,162.304

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014100 · form4.xml · nonDerivative · entry 1

JABRE WISSAM G · CIK 0001903967 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,487.976

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014095 · form4.xml · nonDerivative · entry 1

Donahue Joseph B · CIK 0001413323 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,350.745

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014092 · form4.xml · nonDerivative · entry 1

CANNONE PETER III · CIK 0001276985 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 9,612.08

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014087 · form4.xml · nonDerivative · entry 1

Batra Raj · CIK 0001754514 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,445.339

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-014079 · form4.xml · nonDerivative · entry 1

COLELLA GERARD G · CIK 0001256715 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,216.927

F1 · kind: These restricted stock units become fully vested on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F2 · price: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

SEC source: 0001127602-25-012375 · form4.xml · derivative · entry 3

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 8,291.035

Underlying: Common Stock · 1,740 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 Instruments, Inc.

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

F3 · derivative.exercise_date: These RSUs vest in two equal annual installments commencing on April 17, 2025, provided that if, in any vesting year, April 17th is not a business day, such vesting shall occur on the next business day.

F3 · derivative.expiration_date: These RSUs vest in two equal annual installments commencing on April 17, 2025, provided that if, in any vesting year, April 17th is not a business day, such vesting shall occur on the next business day.