ARCH CAPITAL GROUP LTD. — Director's Dealing 2010

Dec 16, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ARCH CAPITAL GROUP LTD. (ACGL)
CIK: 0000947484
Period of Report: 2010-12-14

Reporting Person: PASQUESI JOHN M (Director, Vice Chairman)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-12-14	Common Shares, $.01 par value per share	M	110000	$20.00	Acquired	120922	Direct
2010-12-14	Common Shares, $.01 par value per share	F	24609	$89.40	Disposed	96313	Direct
2010-12-15	Common Shares, $.01 par value per share	S	39137	$88.8565	Disposed	57176	Direct
2010-12-15	Common Shares, $.01 par value per share	S	46254	$89.2289	Disposed	10922	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-12-14	Stock Option (right to buy)	$20.00	M	110000	Disposed	2011-10-23	Common Shares, $.01 par value per share (110000)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Shares, $.01 par value per share	384268	Indirect
Common Shares, $.01 par value per share	20737	Indirect

Footnotes

F1: The security holder is Otter Capital LLC, for which Mr. Pasquesi serves as managing member. All indicated securities are included because of his affiliation with Otter Capital LLC.

F2: The reporting person contributed his directly owned shares of the company to a revocable trust. The reporting person and his spouse are the trustees.

F3: On December 14, 2010, the reporting person exercised 110,000 stock options and, under the net settlement provisions of the applicable stock option agreement, 24,609 common shares were withheld in payment of the exercise price.

F4: Represents a weighted average sales price; the sales prices range from $88.51 to $88.9975. 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.

F5: Represents a weighted average sales price; the sales prices range from $89.00 to $89.86. 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.