SHC

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: 0001193125-25-310142 · ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI-C, L.P. · CIK 0001550877 · Director · 10% owner

Warburg Pincus (Cayman) XI, L.P. · CIK 0001554853 · Director · 10% owner

Warburg Pincus XI-C, LLC · CIK 0001554852 · Director · 10% owner

Warburg Pincus Partners II (Cayman), L.P. · CIK 0001658820 · Director · 10% owner

Warburg Pincus (Bermuda) Private Equity GP Ltd. · CIK 0001555729 · Director · 10% owner

WARBURG PINCUS LLC · CIK 0001162870 · Director · 10% owner

Warburg Pincus Partners GP LLC · CIK 0001621224 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 34,102,952

F1 · shares: On December 3, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 9,720,000 shares of Common Stock of Sotera Health Company (the "Issuer") pursuant to Rule 144 under the Securities Act of 1933, as amended (the "Sale").

F2 · balance_after: Following the Sale, consists of (i) 27,291,923 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (ii) 6,811,029 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC. Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001193125-25-310134 · ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI-C, L.P. · CIK 0001550877 · Director · 10% owner

Warburg Pincus (Cayman) XI, L.P. · CIK 0001554853 · Director · 10% owner

Warburg Pincus XI-C, LLC · CIK 0001554852 · Director · 10% owner

Warburg Pincus Partners II (Cayman), L.P. · CIK 0001658820 · Director · 10% owner

Warburg Pincus (Bermuda) Private Equity GP Ltd. · CIK 0001555729 · Director · 10% owner

WARBURG PINCUS LLC · CIK 0001162870 · Director · 10% owner

Warburg Pincus Partners GP LLC · CIK 0001621224 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 34,102,952

F1 · shares: On December 3, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 9,720,000 shares of Common Stock of Sotera Health Company (the "Issuer") pursuant to Rule 144 under the Securities Act of 1933, as amended (the "Sale").

F2 · balance_after: Following the Sale, consists of (i) 27,291,923 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (ii) 6,811,029 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC. Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001193125-25-310122 · ownership.xml · nonDerivative · entry 1

GTCR INVESTMENT XI LLC · CIK 0001827977 · Director · 10% owner

GTCR FUND XI/A LP · CIK 0001591434 · Director · 10% owner

GTCR FUND XI/C LP · CIK 0001591436 · Director · 10% owner

GTCR CO-INVEST XI LP · CIK 0001591432 · Director · 10% owner

GTCR PARTNERS XI/A&C LP · CIK 0001828028 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 22,735,301

F1 · shares: On December 3, 2025, the GTCR XI Funds (as defined below) sold a total of 6,480,000 shares of Common Stock of Sotera Health Company (the "Issuer").

F2 · balance_after: Following the sale, consists of (i) 18,044,507 shares of Common Stock held directly by GTCR Fund XI/A LP, a Delaware limited partnership ("Fund XI/A"), (ii) 4,546,174 shares of Common Stock held directly by GTCR Fund XI/C LP, a Delaware limited partnership ("Fund XI/C"), and (iii) 144,620 shares of Common Stock held directly by GTCR Co-Invest XI LP, a Delaware limited partnership ("Co-Invest XI", and together with Fund XI/A and Fund XI/C, the "GTCR XI Funds").

F3 · ownership.nature: GTCR Partners XI/A&C LP ("Partners XI/A&C") is the general partner of each of Fund XI/A and Fund XI/C. GTCR Investment XI LLC ("Investment XI" and together with the GTCR XI Funds and Partners XI/A&C, the "GTCR Entities"), is the general partner of Co-Invest XI and Partners XI/A&C. Investment XI is managed by a board of managers (the "GTCR Board of Managers") consisting of Mark M. Anderson, Aaron D. Cohen, Sean L. Cunningham, David A Donnini, Constantine S. Mihas and Collin E. Roche, and no single person has voting or dispositive authority over the shares of Common Stock.

F4 · ownership.nature: Each of GTCR Partners XI/A&C, GTCR Investment XI and the GTCR Board of Managers may be deemed to share beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds, and each of the individual members of the GTCR Board of Managers disclaims beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds except to the extent of his pecuniary interest therein.

F5 · ownership.nature: Each of the reporting persons is a director-by-deputization solely for purposes of Section 16 of the Exchange Act. Information with respect to each of the GTCR Entities is given solely by such GTCR Entity, and no GTCR Entity has responsibility for the accuracy or completeness of information supplied by another GTCR Entity.

SEC source: 0001999371-25-017526 · warburg_ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI, L.P. · CIK 0001540163 · Director · 10% owner

WP XI Partners, L.P. · CIK 0001540164 · Director · 10% owner

Warburg Pincus XI Partners, L.P. · CIK 0001540386 · Director · 10% owner

Warburg Pincus Private Equity XI-B, L.P. · CIK 0001540166 · Director · 10% owner

Bull Co-Invest L.P. · CIK 0001832693 · Director · 10% owner

Bull Holdco L.P. · CIK 0002014247 · Director · 10% owner

Warburg Pincus XI, L.P. · CIK 0001540167 · Director · 10% owner

WP Global LLC · CIK 0001540385 · Director · 10% owner

Warburg Pincus Partners II, L.P. · CIK 0001658787 · Director

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 43,822,952

F1 · shares: On November 10, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 18,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 14,405,046 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (ii) 3,594,954 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC.Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001999371-25-017529 · warburg_ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI-C, L.P. · CIK 0001550877 · Director · 10% owner

Warburg Pincus (Cayman) XI, L.P. · CIK 0001554853 · Director · 10% owner

Warburg Pincus XI-C, LLC · CIK 0001554852 · Director · 10% owner

Warburg Pincus Partners II (Cayman), L.P. · CIK 0001658820 · Director · 10% owner

Warburg Pincus (Bermuda) Private Equity GP Ltd. · CIK 0001555729 · Director · 10% owner

WARBURG PINCUS LLC · CIK 0001162870 · Director · 10% owner

Warburg Pincus Partners GP LLC · CIK 0001621224 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 43,822,952

F1 · shares: On November 10, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 18,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 14,405,046 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (ii) 3,594,954 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC.Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001193125-25-277915 · ownership.xml · nonDerivative · entry 1

GTCR INVESTMENT XI LLC · CIK 0001827977 · Director · 10% owner

GTCR FUND XI/A LP · CIK 0001591434 · Director · 10% owner

GTCR FUND XI/C LP · CIK 0001591436 · Director · 10% owner

GTCR CO-INVEST XI LP · CIK 0001591432 · Director · 10% owner

GTCR PARTNERS XI/A&C LP · CIK 0001828028 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 29,215,301

F1 · shares: On November 10, 2025, the GTCR XI Funds (as defined below) sold a total of 12,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 23,187,541 shares of Common Stock held directly by GTCR Fund XI/A LP, a Delaware limited partnership ("Fund XI/A"), (ii) 5,841,921 shares of Common Stock held directly by GTCR Fund XI/C LP, a Delaware limited partnership ("Fund XI/C"), and (iii) 185,839 shares of Common Stock held directly by GTCR Co-Invest XI LP, a Delaware limited partnership ("Co-Invest XI", and together with Fund XI/A and Fund XI/C, the "GTCR XI Funds").

F3 · ownership.nature: GTCR Partners XI/A&C LP ("Partners XI/A&C") is the general partner of each of Fund XI/A and Fund XI/C. GTCR Investment XI LLC ("Investment XI" and together with the GTCR XI Funds and Partners XI/A&C, the "GTCR Entities"), is the general partner of Co-Invest XI and Partners XI/A&C. Investment XI is managed by a board of managers (the "GTCR Board of Managers") consisting of Mark M. Anderson, Aaron D. Cohen, Sean L. Cunningham, David A Donnini, Constantine S. Mihas and Collin E. Roche, and no single person has voting or dispositive authority over the shares of Common Stock.

F4 · ownership.nature: Each of GTCR Partners XI/A&C, GTCR Investment XI and the GTCR Board of Managers may be deemed to share beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds, and each of the individual members of the GTCR Board of Managers disclaims beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds except to the extent of his pecuniary interest therein.

F5 · ownership.nature: Each of the reporting persons is a director-by-deputization solely for purposes of Section 16 of the Exchange Act. Information with respect to each of the GTCR Entities is given solely by such GTCR Entity, and no GTCR Entity has responsibility for the accuracy or completeness of information supplied by another GTCR Entity.

SEC source: 0001999371-25-012975 · ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI, L.P. · CIK 0001540163 · Director · 10% owner

WP XI Partners, L.P. · CIK 0001540164 · Director · 10% owner

Warburg Pincus XI Partners, L.P. · CIK 0001540386 · Director · 10% owner

Warburg Pincus Private Equity XI-B, L.P. · CIK 0001540166 · Director · 10% owner

Bull Co-Invest L.P. · CIK 0001832693 · Director · 10% owner

Bull Holdco L.P. · CIK 0002014247 · Director · 10% owner

Warburg Pincus XI, L.P. · CIK 0001540167 · Director · 10% owner

WP Global LLC · CIK 0001540385 · Director · 10% owner

Warburg Pincus Partners II, L.P. · CIK 0001658787 · Director

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 61,822,952

F1 · shares: On September 5, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 12,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 49,475,694 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (ii) 12,347,258 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii) Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global. Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC. Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI, WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001999371-25-012976 · warburg_ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI-C, L.P. · CIK 0001550877 · Director · 10% owner

Warburg Pincus (Cayman) XI, L.P. · CIK 0001554853 · Director · 10% owner

Warburg Pincus XI-C, LLC · CIK 0001554852 · Director · 10% owner

Warburg Pincus Partners II (Cayman), L.P. · CIK 0001658820 · Director · 10% owner

Warburg Pincus (Bermuda) Private Equity GP Ltd. · CIK 0001555729 · Director · 10% owner

WARBURG PINCUS LLC · CIK 0001162870 · Director · 10% owner

Warburg Pincus Partners GP LLC · CIK 0001621224 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 61,822,952

F1 · shares: On September 5, 2025, certain of the Warburg Pincus Entities (as defined below) sold a total of 12,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 49,475,694 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (iii) 12,347,258 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC.Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001193125-25-199493 · ownership.xml · nonDerivative · entry 1

GTCR INVESTMENT XI LLC · CIK 0001827977 · Director · 10% owner

GTCR FUND XI/A LP · CIK 0001591434 · Director · 10% owner

GTCR FUND XI/C LP · CIK 0001591436 · Director · 10% owner

GTCR CO-INVEST XI LP · CIK 0001591432 · Director · 10% owner

GTCR PARTNERS XI/A&C LP · CIK 0001828028 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 41,215,301

F1 · shares: On September 5, 2025, the GTCR XI Funds (as defined below) sold a total of 8,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 32,711,677 shares of Common Stock held directly by GTCR Fund XI/A LP, a Delaware limited partnership ("Fund XI/A"), (ii) 8,241,453 shares of Common Stock held directly by GTCR Fund XI/C LP, a Delaware limited partnership ("Fund XI/C"), and (iii) 262,171 shares of Common Stock held directly by GTCR Co-Invest XI LP, a Delaware limited partnership ("Co-Invest XI", and together with Fund XI/A and Fund XI/C, the "GTCR XI Funds").

F3 · ownership.nature: GTCR Partners XI/A&C LP ("Partners XI/A&C") is the general partner of each of Fund XI/A and Fund XI/C. GTCR Investment XI LLC ("Investment XI" and together with the GTCR XI Funds and Partners XI/A&C, the "GTCR Entities"), is the general partner of Co-Invest XI and Partners XI/A&C. Investment XI is managed by a board of managers (the "GTCR Board of Managers") consisting of Mark M. Anderson, Aaron D. Cohen, Sean L. Cunningham, David A Donnini, Constantine S. Mihas and Collin E. Roche, and no single person has voting or dispositive authority over the shares of Common Stock.

F4 · ownership.nature: Each of GTCR Partners XI/A&C, GTCR Investment XI and the GTCR Board of Managers may be deemed to share beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds, and each of the individual members of the GTCR Board of Managers disclaims beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds except to the extent of his pecuniary interest therein.

F5 · ownership.nature: Each of the reporting persons is a director-by-deputization solely for purposes of Section 16 of the Exchange Act. Information with respect to each of the GTCR Entities is given solely by such GTCR Entity, and no GTCR Entity has responsibility for the accuracy or completeness of information supplied by another GTCR Entity.

SEC source: 0001599220-25-000003 · ownership.xml · nonDerivative · entry 1

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 450,204

F1 · price: Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $16.30 - $16.54. 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.

F2 · balance_after: These securities consist of 80,901 RSUs and 369,303 shares of Common Stock.

SEC source: 0000950170-25-105286 · ownership.xml · nonDerivative · entry 1

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 189,602

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 25,655 Restricted Stock Units ("RSUs"), which represents 33% of the RSU award granted to the Reporting Person on August 7, 2023. These awards were granted pursuant to the terms of RSU agreements 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: 0000950170-25-077776 · ownership.xml · nonDerivative · entry 1

Simon, Christopher · CIK 0001674993 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 19,132

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

SEC source: 0000950170-25-077794 · ownership.xml · nonDerivative · entry 1

MIHAS CONSTANTINE S · CIK 0001262930 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,781

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 61,649 shares of Common Stock.

SEC source: 0000950170-25-077805 · ownership.xml · nonDerivative · entry 1

PETRELLA VINCENT K · CIK 0001276410 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,781

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 61,649 shares of Common Stock.

SEC source: 0000950170-25-077800 · ownership.xml · nonDerivative · entry 1

Neary James · CIK 0001323057 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,781

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 61,649 shares of Common Stock.

SEC source: 0000950170-25-077814 · ownership.xml · nonDerivative · entry 1

Flynn Karen · CIK 0001553599 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 39,221

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 20,089 shares of Common Stock.

SEC source: 0000950170-25-077779 · ownership.xml · nonDerivative · entry 1

Chen Ruoxi · CIK 0001769832 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,781

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incenctive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 61,649 shares of Common Stock.

SEC source: 0000950170-25-077809 · ownership.xml · nonDerivative · entry 1

Wheadon David E. · CIK 0001789507 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 74,912

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 55,780 shares of Common Stock.

SEC source: 0000950170-25-077789 · ownership.xml · nonDerivative · entry 1

Klee Ann R. · CIK 0001796076 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 125,956

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: Consist of 19,132 RSUs and 106,824 shares of Common Stock.

SEC source: 0000950170-25-077811 · ownership.xml · nonDerivative · entry 1

Knauss Robert Brown · CIK 0001951938 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 54,933

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 35,801 shares of Common Stock.

SEC source: 0000950170-25-077785 · ownership.xml · nonDerivative · entry 1

CUNNINGHAM SEAN LAURENCE · CIK 0001829753 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 80,781

F1 · shares: These securities consist of 19,132 restricted stock units ("RSUs") that were granted on May 22, 2025, pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incenctive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs will vest in full on the earlier of (i) the first anniversary of the date of grant, or (ii) the date immediately prior to the Issuer's next regular annual shareholders meeting, subject to the Reporting Person's continued service as a non-employee director of the Issuer through such date.

F2 · balance_after: These securities consist of 19,132 RSUs and 61,649 shares of Common Stock.

SEC source: 0000950170-25-032829 · ownership.xml · derivative · entry 4

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 29,895

Underlying: Common Stock · 29,895 shares

Expires not disclosed

F5 · derivative.exercise_price: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F5 · shares: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F5 · derivative.exercise_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F5 · derivative.expiration_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

SEC source: 0000950170-25-032829 · ownership.xml · nonDerivative · entry 3

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 201,110

F3 · 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 condictions. The RSUs vest in two equal installments on each of March 3, 2026 and March 3, 2027, subject to the Reporting Person's continued service through each such date.

F4 · balance_after: These securities consist of 175,887 RSUs and 25,223 shares of Common Stock.

SEC source: 0000950170-25-032829 · ownership.xml · nonDerivative · entry 2

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 163,741

F2 · 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.

SEC source: 0000950170-25-032826 · ownership.xml · derivative · entry 3

DIMITRIEF ALEXANDER · CIK 0001614732 · SVP, General Counsel and Sec.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 28,026

Underlying: Common Stock · 28,026 shares

Expires not disclosed

F4 · derivative.exercise_price: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

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

F4 · derivative.exercise_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F4 · derivative.expiration_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

SEC source: 0000950170-25-032826 · ownership.xml · nonDerivative · entry 2

DIMITRIEF ALEXANDER · CIK 0001614732 · SVP, General Counsel and Sec.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 334,725

F2 · 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.

F3 · balance_after: These securities consist of 90,323 RSUs and 244,402 shares of Common Stock that have vested.

SEC source: 0000950170-25-032831 · ownership.xml · derivative · entry 5

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 24,289

Underlying: Common Stock · 24,289 shares

Expires not disclosed

F6 · derivative.exercise_price: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F6 · shares: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F6 · derivative.exercise_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

F6 · derivative.expiration_date: These securities consist of a maximum number of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related performance conditions. The additional RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 3, 2026, subject to performance.

SEC source: 0000950170-25-032831 · ownership.xml · nonDerivative · entry 4

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 576,815

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 80,901 RSUs and 495,914 shares of Common Stock. 472,715 of the shares of Common Stock are vested, and 22,199 shares of Common Stock remain subject to vesting conditions. Shares of unvested Common Stock will vest on a daily basis, pro rata through May 13, 2025 (the five year anniversary of the date of grant).

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: 0000950170-25-032829 · ownership.xml · nonDerivative · entry 1

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 103,951

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 13,708 Restricted Stock Units ("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 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: 0000950170-25-032826 · ownership.xml · nonDerivative · entry 1

DIMITRIEF ALEXANDER · CIK 0001614732 · SVP, General Counsel and Sec.

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 278,672

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 17,135 Restricted Stock Units ("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 Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to recieve one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-25-032831 · ownership.xml · nonDerivative · entry 3

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 528,236

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 11,423 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 receive one share of Common Stock, subject to vesting conditions.

SEC source: 0000950170-25-032831 · ownership.xml · nonDerivative · entry 2

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 533,635

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 9,475 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: 0000950170-25-032831 · ownership.xml · nonDerivative · entry 1

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 537,833

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 8,322 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: 0000950170-25-032994 · 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: 0000950170-24-130298 · ownership.xml · nonDerivative · entry 1

Rutz Michael P · CIK 0001599220 · President of Sterigenics

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 541,520

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 6,521 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 61,542 RSUs and 479,978 shares of Common Stock. 425,115 of the shares of Common Stock are vested, and 54,863 shares of Common Stock remain subject to vesting conditions. Shares of unvested Common Stock will vest on a daily basis, pro rata through May 13, 2025 (the five year anniversary of the date of grant).

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: 0001999371-24-011715 · ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI, L.P. · CIK 0001540163 · Director · 10% owner

WP XI Partners, L.P. · CIK 0001540164 · Director · 10% owner

Warburg Pincus XI Partners, L.P. · CIK 0001540386 · Director · 10% owner

Warburg Pincus Private Equity XI-B, L.P. · CIK 0001540166 · Director · 10% owner

Bull Co-Invest L.P. · CIK 0001832693 · Director · 10% owner

Bull Holdco L.P. · CIK 0002014247 · Director · 10% owner

Warburg Pincus XI, L.P. · CIK 0001540167 · Director · 10% owner

WP Global LLC · CIK 0001540385 · Director · 10% owner

Warburg Pincus Partners II, L.P. · CIK 0001658787 · Director

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 73,822,952

F1 · shares: On September 6, 2024, certain of the Warburg Pincus Entities (as defined below) sold a total of 15,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 59,079,058 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (iii) 14,743,894 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii) Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global. Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC. Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI, WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001999371-24-011716 · warburg_ownership.xml · nonDerivative · entry 1

WARBURG PINCUS & CO. · CIK 0000929408 · Director · 10% owner

Warburg Pincus Private Equity XI-C, L.P. · CIK 0001550877 · Director · 10% owner

Warburg Pincus (Cayman) XI, L.P. · CIK 0001554853 · Director · 10% owner

Warburg Pincus XI-C, LLC · CIK 0001554852 · Director · 10% owner

Warburg Pincus Partners II (Cayman), L.P. · CIK 0001658820 · Director · 10% owner

Warburg Pincus (Bermuda) Private Equity GP Ltd. · CIK 0001555729 · Director · 10% owner

WARBURG PINCUS LLC · CIK 0001162870 · Director · 10% owner

Warburg Pincus Partners GP LLC · CIK 0001621224 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 73,822,952

F1 · shares: On September 6, 2024, certain of the Warburg Pincus Entities (as defined below) sold a total of 15,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 59,079,058 shares of Common Stock of the Issuer held by Bull Holdco L.P. ("Bull Holdco") and (iii) 14,743,894 shares of Common Stock of the Issuer held by Bull Co-Invest L.P., a Delaware limited partnership ("Bull Co-Invest").

F3 · ownership.nature: Warburg Pincus XI, L.P., a Delaware limited partnership ("WP XI GP"), is the general partner of each of (i) Warburg Pincus Private Equity XI, L.P. ("WP XI"), (ii)Warburg Pincus Private Equity XI-B, L.P. ("WP XI-B"), (iii) WP XI Partners, L.P. ("WP XI Partners") and (iv) Warburg Pincus XI Partners, L.P. ("Warburg Pincus XI Partners"). WP Global LLC ("WP Global"), is the general partner of WP XI GP. Warburg Pincus Partners II, L.P. ("WPP II"), is the managing member of WP Global.Warburg Pincus Partners GP LLC ("WPP GP LLC"), is the general partner of WPP II. Warburg Pincus & Co. ("WP"), is the managing member of WPP GP LLC.Warburg Pincus (Cayman) XI, L.P. ("WP XI Cayman GP"), is the general partner of Warburg Pincus Private Equity XI-C, L.P. ("WP XI-C" and, together with WP XI,WP XI-B, WP XI Partners and Warburg Pincus XI Partners, the "WP XI Funds").

F4 · ownership.nature: The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are collectively referred to herein as the "Warburg Pincus Entities."

F5 · ownership.nature: Each Warburg Pincus Entity disclaims beneficial ownership with respect to any shares of Common Stock of the Issuer, except to the extent of its pecuniary interest in such shares of Common Stock, if any. The WP XI Funds, Bull Co-Invest, Bull Holdco, WP Global, WPP II, WPP GP LLC, WP XI Cayman GP, WP XI-C LLC, WPP II Cayman, WP Bermuda GP, WP Bull Manager, WP LLC and WP are directors-by-deputization solely for purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Information with respect to each of the Warburg Pincus Entities is given solely by such Warburg Pincus Entity, and no Warburg Pincus Entity has responsibility for the accuracy or completeness of information supplied by another Warburg Pincus Entity.

F6 · ownership.nature: Warburg Pincus XI-C, LLC ("WP XI-C LLC"), is the general partner of WP XI Cayman GP. Warburg Pincus Partners II (Cayman), L.P. ("WPP II Cayman"), is the managing member of WP XI-C LLC. Warburg Pincus (Bermuda) Private Equity GP Ltd. ("WP Bermuda GP"), is the general partner of WPP II Cayman. WP Bull Manager LLC ("WP Bull Manager"), is the general partner of Bull Co-Invest. WP is managing member of WP Bull Manager. Warburg Pincus LLC, a New York limited liability company ("WP LLC"), is the manager of the WP XI Funds. The WP XI Funds share limited partnership ownership in Bull Holdco on a pro rata basis in accordance with their respective numbers of Contributed Shares.

SEC source: 0001999371-24-011707 · ownership.xml · nonDerivative · entry 1

GTCR INVESTMENT XI LLC · CIK 0001827977 · Director · 10% owner

GTCR FUND XI/A LP · CIK 0001591434 · Director · 10% owner

GTCR CO-INVEST XI LP · CIK 0001591432 · Director · 10% owner

GTCR FUND XI/C LP · CIK 0001591436 · Director · 10% owner

GTCR PARTNERS XI/A&C LP · CIK 0001828028 · Director · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 49,215,301

F1 · shares: On September 6, 2024, the GTCR XI Funds (as defined below) sold a total of 10,000,000 shares of Common Stock of Sotera Health Company (the "Issuer") in an underwritten public secondary offering (the "Offering").

F2 · balance_after: Following the Offering, consists of (i) 39,061,101 shares of Common Stock held directly by GTCR Fund XI/A LP, a Delaware limited partnership ("Fund XI/A"), (ii) 9,841,141 shares of Common Stock held directly by GTCR Fund XI/C LP, a Delaware limited partnership ("Fund XI/C"), and (iii) 313,059 shares of Common Stock held directly by GTCR Co-Invest XI LP, a Delaware limited partnership ("Co-Invest XI", and together with Fund XI/A and Fund XI/C, the "GTCR XI Funds").

F3 · ownership.nature: GTCR Partners XI/A&C LP ("Partners XI/A&C") is the general partner of each of Fund XI/A and Fund XI/C. GTCR Investment XI LLC ("Investment XI" and together with the GTCR XI Funds and Partners XI/A&C, the "GTCR Entities"), is the general partner of Co-Invest XI and Partners XI/A&C. Investment XI is managed by a board of managers (the "GTCR Board of Managers") consisting of Mark M. Anderson, Aaron D. Cohen, Sean L. Cunningham, David A Donnini, Constantine S. Mihas and Collin E. Roche, and no single person has voting or dispositive authority over the shares of Common Stock.

F4 · ownership.nature: Each of GTCR Partners XI/A&C, GTCR Investment XI and the GTCR Board of Managers may be deemed to share beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds, and each of the individual members of the GTCR Board of Managers disclaims beneficial ownership of the shares of Common Stock held of record by the GTCR XI Funds except to the extent of his pecuniary interest therein.

F5 · ownership.nature: Each of the reporting persons is a director-by-deputization solely for purposes of Section 16 of the Exchange Act. Information with respect to each of the GTCR Entities is given solely by such GTCR Entity, and no GTCR Entity has responsibility for the accuracy or completeness of information supplied by another GTCR Entity.

SEC source: 0000950170-24-092827 · ownership.xml · nonDerivative · entry 1

Lyons Jonathan M. · CIK 0001983511 · Sr. Vice President, CFO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 110,432

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 25,655 Restricted Stock Units ("RSUs"), which represents 33% of the RSU awards granted to the Reporting Person on August 7, 2023. These awards were granted pursuant to the terms of RSU agreements 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 Common Stock on August 5, 2024.

F3 · balance_after: These securities consist of 92,436 RSUs and 17,996 shares of Common Stock.