BlackRock, Inc. Reports 9.1% Ownership in Waystar Holding Corp

BlackRock, Inc. has filed a Schedule 13G with the SEC, disclosing a 9.1% ownership stake in Waystar Holding Corp. The filing indicates that BlackRock beneficially owns 15,925,871 shares of Waystar's common stock, with sole voting power over 15,729,490 shares and sole dispositive power over all 15,925,871 shares. The filing also notes that various persons have the right to receive dividends or proceeds from the sale of the shares, but no single person's interest exceeds 5% of the total outstanding shares. The filing was made pursuant to Rule 13d-1(b) and was signed by Spencer Fleming, Managing Director of BlackRock, Inc. The effective date of the filing is October 17, 2025.