Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
IORDANOU CONSTANTINE
   2. Issuer Name and Ticker or Trading Symbol
ARCH CAPITAL GROUP LTD. [ACGL] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President & CEO
(Last)
(First)
(Middle)
WESSEX HOUSE, 4TH FLOOR, 45 REID STREET		 3. Date of Earliest Transaction (Month/Day/Year)
02/25/2010
(Street)

HAMILTON, D0 HM 12		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Shares, $.01 par value per share               162,830 (1) D  
Series B Non-Cumulative Preferred Shares (non-convertible)               62,972 D  
Series A Non-Cumulative Preferred Shares (non-convertible)               10,521 D  
Common Shares, $.01 par value per share               129,415 I By Limited Liability Company (2)
Series B Non-Cumulative Preferred Shares (non-convertible)               1,400 I By spouse
Common Shares, $.01 par value per share               7,744 I By children (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Appreciation Right $ 74 02/25/2010   A   70,751   02/25/2010 02/25/2020 Common Shares, $.01 par value per share 70,751 $ 0 70,751 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
IORDANOU CONSTANTINE
WESSEX HOUSE, 4TH FLOOR
45 REID STREET
HAMILTON, D0 HM 12		   X     President & CEO  

Signatures

 /s/ Louis T. Petrillo, Attorney in fact   03/01/2010
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) 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.
(2) 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.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.