The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

Names of Reporting Persons

GTCR INVESTMENT XI LLC

Check The Appropriate Box if a Member of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Citizenship or Place of Organization

Delaware

Number of

Shares

Beneficially

Owned By

Each

Reporting

Person

With

Sole Voting Power

0

Shared Voting Power

175,695,524 (1)

Sole Dispositive Power

0

Shared Dispositive Power

70,278,209

Aggregate Amount Beneficially Owned by Each Reporting Person

175,695,524

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares

☐

Percent of Class Represented By Amount in Row (9)

62.1% (2)

Type of Reporting Person (See Instructions)

OO

As more fully described in Item 4 of this Amendment No. 1 to Schedule 13G, the GTCR Investors are party to a Stockholders Agreement with the Warburg Pincus Investors and certain other holders of Common Stock of the Issuer. The GTCR Investors, together with the Warburg Pincus Investors, hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), of which 105,417,315 shares of Common Stock are publicly reported as being owned by the Warburg Pincus Investors in such entities’ Form 4, filed with the U.S. Securities and Exchange Commission (“Commission”) on March 24, 2021. Although the GTCR Reporting Persons may be deemed to beneficially own the Common Stock held as of record by the Warburg Pincus Investors as a result of the Stockholders Agreement, each GTCR Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock other than the shares of Common Stock of the Issuer owned of record by such GTCR Reporting Person. The percentages used herein have been determined in accordance with footnote 2 below. Capitalized terms used herein are defined in Items 2(a) or 4 below.

Calculated based on 282,916,909 shares of Common Stock outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed on November 10, 2021.

Names of Reporting Persons

GTCR FUND XI/A LP

Check The Appropriate Box if a Member of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Citizenship or Place of Organization

Delaware

Number of

Shares

Beneficially

Owned By

Each

Reporting

Person

With

Sole Voting Power

0

Shared Voting Power

175,695,524 (1)

Sole Dispositive Power

0

Shared Dispositive Power

55,778,268

Aggregate Amount Beneficially Owned by Each Reporting Person

175,695,524

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares

☐

Percent of Class Represented By Amount in Row (9)

62.1% (2)

Type of Reporting Person (See Instructions)

PN

As more fully described in Item 4 of this Amendment No. 1 to Schedule 13G, the GTCR Investors are party to a Stockholders Agreement with the Warburg Pincus Investors and certain other holders of Common Stock of the Issuer. The GTCR Investors, together with the Warburg Pincus Investors, hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), of which 105,417,315 shares of Common Stock are publicly reported as being owned by the Warburg Pincus Investors in such entities’ Form 4, filed with the Commission on March 24, 2021. Although the GTCR Reporting Persons may be deemed to beneficially own the Common Stock held as of record by the Warburg Pincus Investors as a result of the Stockholders Agreement, each GTCR Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock other than the shares of Common Stock of the Issuer owned of record by such GTCR Reporting Person. The percentages used herein have been determined in accordance with footnote 2 below. Capitalized terms used herein are defined in Items 2(a) or 4 below.

Calculated based on 282,916,909 shares of Common Stock outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed on November 10, 2021.

Names of Reporting Persons

GTCR FUND XI/C LP

Check The Appropriate Box if a Member of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Citizenship or Place of Organization

Delaware

Number of

Shares

Beneficially

Owned By

Each

Reporting

Person

With

Sole Voting Power

0

Shared Voting Power

175,695,524 (1)

Sole Dispositive Power

0

Shared Dispositive Power

14,052,901

Aggregate Amount Beneficially Owned by Each Reporting Person

175,695,524

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares

☐

Percent of Class Represented By Amount in Row (9)

62.1% (2)

Type of Reporting Person (See Instructions)

PN

As more fully described in Item 4 of this Amendment No. 1 to Schedule 13G, the GTCR Investors are party to a Stockholders Agreement with the Warburg Pincus Investors and certain other holders of Common Stock of the Issuer. The GTCR Investors, together with the Warburg Pincus Investors, hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), of which 105,417,315 shares of Common Stock are publicly reported as being owned by the Warburg Pincus Investors in such entities’ Form 4, filed with the Commission on March 24, 2021. Although the GTCR Reporting Persons may be deemed to beneficially own the Common Stock held as of record by the Warburg Pincus Investors as a result of the Stockholders Agreement, each GTCR Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock other than the shares of Common Stock of the Issuer owned of record by such GTCR Reporting Person. The percentages used herein have been determined in accordance with footnote 2 below. Capitalized terms used herein are defined in Items 2(a) or 4 below.

Calculated based on 282,916,909 shares of Common Stock outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed on November 10, 2021.

Names of Reporting Persons

GTCR CO-INVEST XI LP

Check The Appropriate Box if a Member of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Citizenship or Place of Organization

Delaware

Number of

Shares

Beneficially

Owned By

Each

Reporting

Person

With

Sole Voting Power

0

Shared Voting Power

175,695,524 (1)

Sole Dispositive Power

0

Shared Dispositive Power

447,040

Aggregate Amount Beneficially Owned by Each Reporting Person

175,695,524

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares

☐

Percent of Class Represented By Amount in Row (9)

62.1% (2)

Type of Reporting Person (See Instructions)

PN

As more fully described in Item 4 of this Amendment No. 1 to Schedule 13G, the GTCR Investors are party to a Stockholders Agreement with the Warburg Pincus Investors and certain other holders of Common Stock of the Issuer. The GTCR Investors, together with the Warburg Pincus Investors, hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), of which 105,417,315 shares of Common Stock are publicly reported as being owned by the Warburg Pincus Investors in such entities’ Form 4, filed with the Commission on March 24, 2021. Although the GTCR Reporting Persons may be deemed to beneficially own the Common Stock held as of record by the Warburg Pincus Investors as a result of the Stockholders Agreement, each GTCR Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock other than the shares of Common Stock of the Issuer owned of record by such GTCR Reporting Person. The percentages used herein have been determined in accordance with footnote 2 below. Capitalized terms used herein are defined in Items 2(a) or 4 below.

Calculated based on 282,916,909 shares of Common Stock outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed on November 10, 2021.

Names of Reporting Persons

GTCR PARTNERS XI/A&C LP

Check The Appropriate Box if a Member of a Group (See Instructions)

(a)  ☐        (b)  ☒

SEC Use Only

Citizenship or Place of Organization

Delaware

Number of

Shares

Beneficially

Owned By

Each

Reporting

Person

With

Sole Voting Power

0

Shared Voting Power

175,695,524 (1)

Sole Dispositive Power

0

Shared Dispositive Power

70,278,209

Aggregate Amount Beneficially Owned by Each Reporting Person

175,695,524

Check Box if the Aggregate Amount in Row (9) Excludes Certain Shares

☐

Percent of Class Represented By Amount in Row (9)

62.1% (2)

Type of Reporting Person (See Instructions)

PN

As more fully described in Item 4 of this Amendment No. 1 to Schedule 13G, the GTCR Investors are party to a Stockholders Agreement with the Warburg Pincus Investors and certain other holders of Common Stock of the Issuer. The GTCR Investors, together with the Warburg Pincus Investors, hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), of which 105,417,315 shares of Common Stock are publicly reported as being owned by the Warburg Pincus Investors in such entities’ Form 4, filed with the Commission on March 24, 2021. Although the GTCR Reporting Persons may be deemed to beneficially own the Common Stock held as of record by the Warburg Pincus Investors as a result of the Stockholders Agreement, each GTCR Reporting Person expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock other than the shares of Common Stock of the Issuer owned of record by such GTCR Reporting Person. The percentages used herein have been determined in accordance with footnote 2 below. Capitalized terms used herein are defined in Items 2(a) or 4 below.

Calculated based on 282,916,909 shares of Common Stock outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed on November 10, 2021.

Names of Persons Filing

This Amendment No. 1 to Schedule 13G is being filed jointly by (i) GTCR Fund XI/A LP, a Delaware limited partnership (“Fund XI/A”), (ii) GTCR Fund XI/C LP, a Delaware limited partnership (“Fund XI/C”), (iii) 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”), (iv) GTCR Partners XI/A&C LP, a Delaware limited partnership (“Partners XI/A&C”) and the general partner of each of Fund XI/A and Fund XI/C, and (v) GTCR Investment XI LLC, a Delaware limited liability company (“Investment XI”) and 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, Craig A. Bondy, Aaron D. Cohen, Sean L. Cunningham, Benjamin J. Daverman, 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. The GTCR XI Funds, Partners XI/A&C and Investment XI are collectively referred to herein as the “GTCR Reporting Persons”.

The principal business address of each of the GTCR Reporting Persons is 300 North LaSalle Street, Suite 5600, Chicago, IL 60654.

indemnification matters. Pursuant to the Stockholders Agreement, each of the Warburg Pincus Sponsors and the GTCR XI Funds has agreed to vote the shares of Common Stock of the Issuer that each holds of record in a certain manner on matters related to the election of certain directors appointed by the Warburg Pincus Sponsors and the GTCR XI Funds. The Warburg Pincus Sponsors and the GTCR XI Funds hold an aggregate total of 175,695,524 shares of Common Stock of the Issuer (approximately 62.1% of the outstanding shares of Common Stock of the Issuer), including 70,278,209 shares of Common Stock of the Issuer that are publicly reported as being owned by the GTCR XI Funds and 105,417,315 shares of Common Stock of the Issuer that are publicly reported as being owned by the Warburg Pincus Sponsors. The GTCR Reporting Persons are not entitled to any rights as a stockholder of the Issuer with respect to the shares of Common Stock of the Issuer beneficially owned by the Other Investors or the Warburg Pincus Sponsors except as expressly set forth in the Stockholders Agreement and the GTCR Reporting Persons do not have dispositive power over the Common Stock owned by the Warburg Pincus Sponsors. Each GTCR Reporting Person and each of the individual members of the GTCR Board of Managers expressly disclaims beneficial ownership (within the meaning of Rule 13d-3 of the Exchange Act) with respect to any shares of Common Stock of the Issuer other than the shares of Common Stock of the Issuer owned of record by a GTCR Reporting Person. The number of shares of Common Stock of the Issuer owned by each GTCR Reporting Person as set forth in Rows 5 – 11 of their respective cover pages to this Schedule 13G does not reflect the aggregate shares of Common Stock of the Issuer owned by the Other Investors.

The aggregate total of 105,417,315 shares of Common Stock of the Issuer indicated in this Amendment No. 1 to Schedule 13G as being beneficially owned by the Warburg Pincus Sponsors is derived from the Warburg Pincus Sponsors’ Form 4, filed with the U.S. Securities and Exchange Commission (the “Commission”) on March 24, 2021, and is not purported to be an accurate representation of the Warburg Pincus Sponsors’ beneficial ownership as of the date of this Amendment No. 1 to Schedule 13G. The Warburg Pincus Sponsors are responsible for reporting their beneficial ownership of shares of Common Stock of the Issuer on their own behalf, and the GTCR Reporting Persons disclaim responsibility for reporting the shares of Common Stock of the Issuer beneficially owned by the Warburg Pincus Sponsors.

The percentages used herein are calculated based on 282,916,909 shares of Common Stock of Sotera Health Company (the “Issuer”) outstanding as of November 3, 2021 as reported on the Issuer’s Form 10-Q, filed with the Commission on November 10, 2021.