ACGL: Material agreement · Other company developments

ITEM 1.01 Entry into a Material Definitive Agreement. On June 2, 2026, Arch Capital Group Ltd. (“ACGL” or the “Issuer”) entered into an Underwriting Agreement pursuant to which the Issuer agreed to sell, and the underwriters named therein agreed to purchase, subject to and upon terms and conditions set forth therein, (i) $600,000,000 aggregate principal amount of 5.250% senior notes due 2036 (the “2036 Notes”) and (ii) $1,400,000,000 aggregate principal amount of 5.950% senior notes due 2056 (the “2056 Notes” and, together with the 2036 Notes, the “Notes”). The offering was made pursuant to an effective shelf registration statement and a prospectus supplement and is expected to close on June 9, 2026. A copy of the Underwriting Agreement is attached to this Current Report on Form 8-K as Exhibit 1.1 and is incorporated herein by reference. ITEM 8.01 Other Events . On June 2, 2026, ACGL issued a press release announcing it priced the underwritten public offering of the Notes. A copy of the press release is attached to this Current Report on Form 8-K as Exhibit 99.1 and is incorporated herein by reference. ITEM 9.01 Financial Statements and Exhibits . (d): The following exhibits are being filed herewith. EXHIBIT NO. DESCRIPTION 1.1 Underwriting Agreement, dated as of June 2, 2026, by and among Arch Capital Group Ltd., and Wells Fargo Securities, LLC, BofA Securities, Inc., J.P. Morgan Securities LLC, and Lloyds Securities Inc., as representatives of the underwriters named therein. 99.1 Press release dated June 2, 2026 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) 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 undersign