ACGL: Leadership change

ITEM 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. (b) On October 26, 2026, Moira Kilcoyne resigned from her position as a member of the Board of Directors (the “Board”) of Arch Capital Group Ltd. (the “Company”), effective immediately. Her resignation was not because of a disagreement with Arch on any matter relating to Arch’s operations, policies, or practices. The Board and management thank Ms. Kilcoyne for her service and contributions to the Company, informed by her extensive financial services experience, which has supported the business through a period of strong financial performance. 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. ARCH CAPITAL GROUP LTD. Date: October 29, 2026 By: /s/ François Morin Name: François Morin Title: Executive Vice President, Chief Financial Officer and Treasurer 3