Advent International's Schedule 13D Filing for Waystar Holding Corp.

Advent International, L.P., along with its affiliates Advent International GP, LLC and AIO Holdings L.P., filed a Schedule 13D with the SEC regarding their holdings in Waystar Holding Corp. The filing discloses that the Reporting Persons collectively own approximately 5.8% of Waystar's common stock, acquired through a merger with Iodine Software Holdings, Inc. The merger, completed on October 1, 2025, involved a cash consideration of approximately $458.6 million and the issuance of 16.6 million shares of common stock. The Reporting Persons hold the shares for investment purposes and may increase or decrease their position in Waystar depending on various factors, including market conditions and the company's performance. The filing also details agreements related to the merger, including a Stockholder and Lockup Agreement and a Joinder Agreement to the Registration Rights Agreement.