Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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: 3235-0104
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
  GRANDISSON MARC
 2. Date of Event Requiring Statement (Month/Day/Year)
04/05/2004		 3. Issuer Name and Ticker or Trading Symbol
ARCH CAPITAL GROUP LTD. [ACGL]
(Last)
(First)
(Middle)
WESSEX HOUSE, 45 REID STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Reinsur. Group Chairman & CEO
 5. If Amendment, Date Original Filed(Month/Day/Year)
04/05/2005
(Street)

HAMILTON, D0 HM 12		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Shares, $.01 par value per share 22,453 (1)
D
 
Common Shares, $.01 par value per share 220
I
By spouse

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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.

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy)   (2) 10/23/2011 Common Shares, $.01 par value per share 37,500 $ 20 D  
Series A Convertible Preference Shares (3)   (3)   (3) Common Shares, $.01 par value per share 12,905 $ (3) D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
GRANDISSON MARC
WESSEX HOUSE, 45 REID STREET
HAMILTON, D0 HM 12		       Reinsur. Group Chairman & CEO  

Signatures

/s/ Marc Grandisson 02/27/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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) 12,500 of such shares are restricted and subject to vesting on October 23, 2006; 1,926 of such shares are restricted and subject to vesting in two equal annual installments on February 20, 2005 and 2006; 2148 of such shares are restricted and subject to vesting in three equal annual installments on February 26, 2005, 2006 and 2007.
(2) The stock option became exercisable in three equal annual installments commencing on October 23, 2001.
(3) Subject to certain restrictions on conversion, the Series A Convertible Preference Shares are convertible on a one-for-one basis into Common Shares at the option of the holder and are manditorily convertible into Common Shares upon the occurrence of certain events. The conversion ratio is subject to antidilution and other adjustments.

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.