ARCH CAPITAL GROUP LTD. — Director's Dealing 2010

May 11, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ARCH CAPITAL GROUP LTD. (ACGL)
CIK: 0000947484
Period of Report: 2010-05-09

Reporting Person: PETRILLO LOUIS T (Officer of Subsidiary)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-09	Common Shares, $.01 par value per share	F	670	—	Disposed	27771	Direct
2010-05-11	Common Shares, $.01 par value per share	F	703	—	Disposed	27068	Direct

Footnotes

F1: Represents shares withheld to pay taxes due upon the vesting of restricted stock.