X0609 4 2026-08-18 0 0000947484 ARCH CAPITAL GROUP LTD. ACGL 0001741826 Morin Francois true WATERLOO HOUSE, GROUND FLOOR 100 PITTS BAY ROAD PEMBROKE D0 HM 08 BERMUDA 0 1 0 0 CFO and Treasurer 0 Common Shares, $.0011 par value per share 2026-08-18 4 M 0 11010 27.0867 A 195836 D Common Shares, $.0011 par value per share 2026-08-18 4 S 0 11010 99.3214 D 184826 D Common Shares, $.0011 par value per share 114229 I By Trust Stock Option (Right to Buy) 27.0867 2026-08-18 4 M 0 11010 0 D 2027-05-08 Common Shares, $.0011 par value per share 11010 0 D The price reported is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $99.14 to $99.56. Upon request, the full information regarding the number of shares sold at each separate price within the range will be provided to the issuer, any security holder of the issuer or the staff of the Securities Exchange Commission. Amount includes 267 Common Shares acquired on May 29, 2026 under the Arch Capital Group Ltd. Employee Share Purchase Plan. The shares were previously owned directly in a joint account with the insider's spouse and were contributed to a revocable trust for the benefit of the insider's spouse. This stock option is exercisable in three equal annual installments commencing May 8, 2018, and the next two installments on May 8, 2019 and May 8, 2020, subject to the applicable award agreement. /s/ Louis Petrillo, Attorney-in-Fact 2026-08-20