X0202 4 2005-12-30 0 0000947484 ARCH CAPITAL GROUP LTD. ACGL 0001114751 INGREY PAUL B WESSEX HOUSE, 4TH FLOOR 45 REID STREET HAMILTON D0 HM 12 BERMUDA 1 0 0 1 Chairman of the Board Common Shares, $.01 par value per share 2005-12-30 4 C 0 103242 A 380652 D Series A Convertible Preference Shares 2005-12-30 4 C 0 103242 D Common Shares, $.01 par value per share 103242 0 D Subject to certain restrictions on conversion, the Series A Convertible Preference are convertible on a one-for-one basis into Common Shares at the option of the holder and are mandatorily convertible into Common Shares upon the occurrence of certain events. The conversion ratio is subject to antidilution and other adjustments. Louis T. Petrillo Attorney in fact 2005-12-30