ARCH CAPITAL GROUP LTD. — Director's Dealing 2010

Mar 1, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: ARCH CAPITAL GROUP LTD. (ACGL)
CIK: 0000947484
Period of Report: 2010-02-25

Reporting Person: IORDANOU CONSTANTINE (Director, President & CEO)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-02-25	Stock Appreciation Right	$74.00	A	70751	Acquired	2020-02-25	Common Shares, $.01 par value per share (70751)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Shares, $.01 par value per share	162830	Direct
Series B Non-Cumulative Preferred Shares (non-convertible)	62972	Direct
Series A Non-Cumulative Preferred Shares (non-convertible)	10521	Direct
Common Shares, $.01 par value per share	129415	Indirect
Series B Non-Cumulative Preferred Shares (non-convertible)	1400	Indirect
Common Shares, $.01 par value per share	7744	Indirect

Footnotes

F1: The reporting person no longer has a reportable beneficial ownership interest in 3,872 common shares owned by one of his children and included in the reporting person's prior ownership reports. Prior ownership reports regarding beneficial ownership by children had incorrectly reported an indirect beneficial ownership of 50 common shares which should have been reported as owned directly. These common shares are included in the totals on this form. In addition, 11,850 common shares and 3,000 Series B Non-Cumulative Preferred Shares (non-convertible) formerly reported as indirectly held by the reporting person through irrevocable trusts for the benefit of his children are no longer reported since the trustee of the trusts is an independent trustee and the shares are, therefore, not treated as directly or indirectly owned by the reporting person.

F2: The shares are owned by Mathiatis LLC, a limited liability company. The reporting person owns all of the membership interests in Mathiatis LLC and serves at its sole managing member.