GTCR Entities Amend Schedule 13G for Sotera Health Co. Holdings

This filing is an amendment (No. 5) to Schedule 13G, jointly filed by GTCR Investment XI LLC and its affiliated entities (collectively, "GTCR Reporting Persons"). The filing concerns Sotera Health Co. ("Issuer") and reports beneficial ownership of the Issuer's common stock. As of October 28, 2025, the GTCR Reporting Persons, along with Warburg Pincus Investors, hold an aggregate of 56,838,253 shares, representing approximately 20.0% of the outstanding common stock. This joint filing is made due to the possibility that the GTCR Reporting Persons may be considered a "group" under the Exchange Act. The filing details the ownership breakdown among the GTCR entities, noting that while they may be deemed to beneficially own shares held by Warburg Pincus Investors due to a Stockholders Agreement, each GTCR Reporting Person disclaims beneficial ownership beyond the shares they hold of record. The information regarding Warburg Pincus Investors' ownership is derived from their separate Form 4 filing.