ARCH CAPITAL GROUP LTD. — Director's Dealing 2010

May 13, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ARCH CAPITAL GROUP LTD. (ACGL)
CIK: 0000947484
Period of Report: 2010-05-11

Reporting Person: Lyons Mark Donald (Chairman & CEO Arch Insur Gr)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-11	Common Shares, $.01 par value per share	F	1065	$75.19	Disposed	60903	Direct

Footnotes

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