ARCH CAPITAL GROUP LTD. — Director's Dealing 2010

May 20, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ARCH CAPITAL GROUP LTD. (ACGL)
CIK: 0000947484
Period of Report: 2010-05-18

Reporting Person: Vollaro John D (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-05-18	Common Shares, $.01 par value per share	S	4000	$75.32	Disposed	46600	Direct

Footnotes

F1: Represents a weighted average sale price; the sales prices ranged from $75.22 to $75.39. Upon request, the full sale information regarding the number of shares sold at each price increment will be provided to the Commission or a security holder of the issuer.