Petras Michael B. Jr.

SEC source: 0001193125-26-356962 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Director · Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 3,969,393

F2 · price: Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $18.50 - $18.855. The reporting person hereby undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

SEC source: 0001193125-26-356962 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 397,912

F1 · price: Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $18.50 - $18.855. The reporting person hereby undertakes, upon request by the Commission staff, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

SEC source: 0001193125-26-092231 · ownership.xml · derivative · entry 9

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 120,124

Underlying: Common Stock · 120,124 shares

Expires not disclosed

F7 · derivative.exercise_price: These securities consist of a maximum number of SAUs that were granted on March 2, 2026, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related peformance conditions. The SAUs generally vest annually in 60%, 20% and 20% installments, respectively, commencing March 2027, subject to performance.

F7 · derivative.exercise_date: These securities consist of a maximum number of SAUs that were granted on March 2, 2026, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related peformance conditions. The SAUs generally vest annually in 60%, 20% and 20% installments, respectively, commencing March 2027, subject to performance.

F7 · derivative.expiration_date: These securities consist of a maximum number of SAUs that were granted on March 2, 2026, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related peformance conditions. The SAUs generally vest annually in 60%, 20% and 20% installments, respectively, commencing March 2027, subject to performance.

SEC source: 0001193125-26-092231 · ownership.xml · derivative · entry 8

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 59,790

Underlying: Common Stock · 89,686 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.

F3 · derivative.exercise_price: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

F3 · price: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

F3 · derivative.exercise_date: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

F3 · derivative.expiration_date: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 6

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 692,427

F6 · shares: These securities consist of RSUs that were granted on March 2, 2026, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 2027.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 5

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 452,179

F5 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 179,372 RSUs granted to the Reporting Person on March 3, 2025. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to recieve one share of Common Stock, subject to vesting conditions.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 4

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 531,283

F4 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 89,686 SAUs granted to the Reporting Person on March 3, 2025. This award was granted pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represents the Reporting Person's right to recieve one share of Common Stock, subject to performance.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 570,835

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.

F3 · shares: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

F3 · price: These securities consist of performance-based share appreciation units ("SAUs") (formerly called performance stock units) that were granted on March 3, 2025, pursuant to the terms of a SAU Agreement under the 2020 Incentive Plan. Each SAU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the SAUs, the Reporting Person vested in 89,686 shares of Common Stock on March 2, 2026. The remaining SAUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 481,149

F2 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 91,386 RSUs granted to the Reporting Person on March 4, 2024. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to recieve one share of Common Stock, subject to vesting conditions.

SEC source: 0001193125-26-092231 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 521,451

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 71,063 Restricted Stock Units ("RSUs") granted to the Reporting Person on March 6, 2023. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions

SEC source: 0001193125-25-314343 · ownership.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Family Trust

Disclosed balance after: 0

SEC source: 0001193125-25-314343 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 4,819,393

SEC source: 0001193125-25-314343 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 552,790

SEC source: 0000950170-25-032994 · ownership.xml · derivative · entry 7

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 149,476

Underlying: Common Stock · 149,476 shares

Expires not disclosed

F7 · derivative.exercise_price: These securities consist of a maximum number of Performance Stock Units ("PSUs") that were granted on March 3, 2025, pursuant to the terms of a PSU agreement under the 2020 Incentive Plan. Each PSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The PSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F7 · shares: These securities consist of a maximum number of Performance Stock Units ("PSUs") that were granted on March 3, 2025, pursuant to the terms of a PSU agreement under the 2020 Incentive Plan. Each PSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The PSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F7 · derivative.exercise_date: These securities consist of a maximum number of Performance Stock Units ("PSUs") that were granted on March 3, 2025, pursuant to the terms of a PSU agreement under the 2020 Incentive Plan. Each PSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The PSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F7 · derivative.expiration_date: These securities consist of a maximum number of Performance Stock Units ("PSUs") that were granted on March 3, 2025, pursuant to the terms of a PSU agreement under the 2020 Incentive Plan. Each PSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The PSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

SEC source: 0000950170-25-032994 · ownership.xml · nonDerivative · entry 4

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 868,603

F4 · shares: These securities consist of RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026.

F5 · balance_after: These securities consist of 552,790 RSUs and 315,813 shares of Common Stock.

SEC source: 0000950170-25-032994 · ownership.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 569,650

F3 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 91,386 RSUs, which represents 33% of the RSU award granted to the Reporting Person on March 4, 2024. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to recieve one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-25-032994 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 610,637

F2 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 71,063 RSUs, which represents 33% of the RSU award granted to the Reporting Person on March 6, 2023. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-25-032994 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 642,509

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 62,407 Restricted Stock Units ("RSUs"), which represents 33% of the RSU award granted to the Reporting Person on March 2, 2022. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-24-130309 · ownership.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Family Trust

Disclosed balance after: 39,243

F3 · balance_after: The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported shares for purposes of Section 16 or for any other purpose.

SEC source: 0000950170-24-130309 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 5,214,337

SEC source: 0000950170-24-130309 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 670,499

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 65,217 Restricted Stock Units ("RSUs"), which represents 25% of the RSU award granted to the Reporting Person on November 20, 2020. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

F2 · balance_after: These securities consist of 478,693 RSUs and 191,806 shares of Common Stock.

SEC source: 0000950170-24-105933 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 5,253,580

F1 · shares: Represents a gift of issuer securities by the reporting person to a charitable foundation. The recipient of the gifted securities has executed a lock-up agreement equivalent to the lock-up agreement entered into with respect to the September 6, 2024 registered stock offering.

SEC source: 0000950170-24-026347 · ownership.xml · derivative · entry 5

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 544,509

Underlying: Common Stock · 544,509 shares

Expires 2034-03-04

F7 · derivative.exercise_date: These options were granted on March 4, 2024, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest annually in three equal installments commencing March 2, 2025, subject to vesting conditions.

F7 · balance_after: These options were granted on March 4, 2024, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest annually in three equal installments commencing March 2, 2025, subject to vesting conditions.

SEC source: 0000950170-24-026347 · ownership.xml · nonDerivative · entry 4

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 5,453,580

F5 · shares: On March 4, 2024, the Reporting Person sold a total of 1,003,870 shares of Common Stock of the Issuer in an underwritten public secondary offering (the "Offering").

F6 · price: Reflects a price equal to the Offering price per share less underwriting discounts and commissions payable thereon, as disclosed in the Issuer's Prospectus 424(b)(7), filed with the United States Securities and Exchange Commission on February 29, 2024.

SEC source: 0000950170-24-026347 · ownership.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 699,749

F3 · shares: These securities consist of RSUs that were granted on March 4, 2024, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs vest annually in three equal installments commencing March 2, 2025.

F4 · balance_after: These securities consist of 543,910 RSUs and 155,839 shares of Common Stock.

SEC source: 0000950170-24-026347 · ownership.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 425,589

F2 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 71,063 RSUs, which represents 33% of the RSU award granted to the Reporting Person on March 6, 2023. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-24-026347 · ownership.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 447,163

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 62,406 Restricted Stock Units ("RSUs"), which represents 33% of the RSU award granted to the Reporting Person on March 2, 2022. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

SEC source: 0001822479-23-000070 · wk-form4_1700687309.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 555,418

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 65,217 Restricted Stock Units ("RSUs"), which represents 25% of the RSU award granted to the Reporting Person on November 20, 2020. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

F2 · price: Represents the closing price of the Company's Common Stock on November 20, 2023.

F3 · balance_after: These securities consist of 403,219 RSUs and 152,199 shares of Common Stock.

SEC source: 0001822479-23-000021 · wf-form4_167831492828392.xml · derivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 404,094

Underlying: Common Stock · 404,094 shares

Expires 2033-03-06

F4 · derivative.exercise_date: These options were granted on March 6, 2023, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest annually in three equal installments commencing March 2, 2024, subject to vesting conditions.

F4 · balance_after: These options were granted on March 6, 2023, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest annually in three equal installments commencing March 2, 2024, subject to vesting conditions.

SEC source: 0001822479-23-000021 · wf-form4_167831492828392.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 584,668

F1 · shares: These securities consist of Restricted Stock Units ("RSUs") that were granted on March 6, 2023, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs vest annually in three equal installments commencing March 2, 2024.

F2 · balance_after: These securities consist of 468,436 RSUs and 116,232 shares of Common Stock.

SEC source: 0001822479-23-000017 · wf-form4_167814642447695.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 371,479

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 62,406 Restricted Stock Units ("RSUs"), which represents 33% of the RSU award granted to the Reporting Person on March 2, 2022. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

F2 · price: Represents the closing price of the Company's Common Stock on March 2, 2023.

F3 · balance_after: These securities consist of 255,247 RSUs and 116,232 shares of Common Stock.

SEC source: 0001822479-22-000080 · wf-form4_166915442637925.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 391,320

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 65,218 Restricted Stock Units ("RSUs"), which represents 25% of the RSU award granted to the Reporting Person on November 20, 2020. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

F2 · price: Represents the closing price of the Company's Common Stock on November 18, 2022.

F3 · balance_after: These securities consist of 317,653 RSUs and 73,667 shares of Common Stock.

SEC source: 0001822479-22-000078 · wf-form4_166803242535825.xml · derivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 2,108,356

Underlying: Common Stock · 2,108,356 shares

Expires 2032-11-07

F3 · derivative.exercise_date: These options were granted on November 7, 2022, pursuant to the terms of a stock option agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). The options vest in three installments, as follows: 30%, 30%, and 40% of the options vest on each of the 12-month, 18-month, and 24-month anniversaries, respectively, of the date of grant, subject to the Reporting Person's continued service through each such date.

F3 · balance_after: These options were granted on November 7, 2022, pursuant to the terms of a stock option agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). The options vest in three installments, as follows: 30%, 30%, and 40% of the options vest on each of the 12-month, 18-month, and 24-month anniversaries, respectively, of the date of grant, subject to the Reporting Person's continued service through each such date.

SEC source: 0001822479-22-000019 · wf-form4_164642836722086.xml · derivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 478,932

Underlying: Common Stock · 478,932 shares

Expires 2032-03-02

F4 · derivative.exercise_date: These options were granted on March 2, 2022, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest in three equal installments on each of the first three anniversaries of the date of grant, subject to the Reporting Person's continued service through each such date.

F4 · balance_after: These options were granted on March 2, 2022, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest in three equal installments on each of the first three anniversaries of the date of grant, subject to the Reporting Person's continued service through each such date.

SEC source: 0001822479-22-000019 · wf-form4_164642836722086.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 420,571

F1 · shares: These securities consist of Restricted Stock Units ("RSUs") that were granted on March 2, 2022, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of common stock, subject to vesting conditions. The RSUs vest in three equal installments on each of the first three anniversaries of the date of grant, subject to the Reporting Person's continued service through each such date.

F2 · balance_after: These securities consists of 382,871 RSUs and 37,700 shares of Common Stock.

SEC source: 0001822479-21-000076 · wf-form4_163771559892577.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 233,352

F1 · shares: These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 65,217 Restricted Stock Units ("RSUs"), which represents 25% of the RSU award granted to the Reporting Person on November 20, 2020. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

F2 · balance_after: These securities consists of 195,652 RSUs and 37,700 shares of Common Stock.

SEC source: 0001628280-21-005471 · wf-form4_161661805855061.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 6,377,185

F1 · shares: On March 22, 2021, Mr. Petras sold a total of 817,439 shares of Common Stock of Sotera Health Company in an underwritten public secondary offering (the "Offering").

F2 · price: Reflects a price equal to the Offering price per share less underwriting discounts and commissions payable thereon, as disclosed in the company's Prospectus 424(b)(4), filed with the United States Securities and Exchange Commission on March 18, 2021.

SEC source: 0000899243-20-032076 · doc4.xml · nonDerivative · entry 3

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Indirect · By Grantor Trust

Disclosed balance after: 7,194,624

F2 · price: Reflects a company repurchase price equal to the initial public offering price per share less underwriting discounts and commissions payable thereon, as disclosed in the company's Registration Statement on Form S-1.

SEC source: 0000899243-20-032076 · doc4.xml · nonDerivative · entry 2

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Indirect · By Grantor Retained Annuity Trust

Disclosed balance after: 0

F2 · price: Reflects a company repurchase price equal to the initial public offering price per share less underwriting discounts and commissions payable thereon, as disclosed in the company's Registration Statement on Form S-1.

SEC source: 0000899243-20-032076 · doc4.xml · derivative · entry 4

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,118,012

Underlying: Common Stock · 1,118,012 shares

Expires 2030-11-20

F3 · derivative.exercise_date: These options were granted on November 20, 2020, pursuant to the terms of a stock option agreement under the 2020 Incentive Plan. The options vest in four equal installments on each of the first four anniversaries of the date of grant, subject to the Reporting Person's continued service through each such date.

SEC source: 0000899243-20-032076 · doc4.xml · nonDerivative · entry 1

Petras Michael B. Jr. · CIK 0001832387 · Director · Chairman & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 260,869

F1 · shares: These securities consist of Restricted Stock Units ("RSUs") that were granted on November 20, 2020, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of common stock, subject to vesting conditions. The RSUs vest in four equal installments on each of the first four anniversaries of the date of grant, subject to the Reporting Person's continued service through each such date.