UNITED STATES

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

Current Report Pursuant to Section 13 or 15(d)
of the Securities Exchange Act of 1934

October 23, 2008

Date of Report (Date of earliest event reported)

Arch Capital Group Ltd.

(Exact name of registrant as specified in its charter)

Bermuda		0-26456		N/A
(State or other jurisdiction of incorporation or organization)		(Commission File Number)		(I.R.S. Employer Identification No.)

Wessex House, 45 Reid Street, Hamilton HM 12, Bermuda

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code:
(441) 278-9250

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

ITEM 2.02 Results of Operations and Financial Condition.

On October 23, 2008, Arch Capital Group Ltd. issued a press release reporting its earnings and the availability of its third quarter financial supplement for the three and nine month periods ended September 30, 2008. The press release and financial supplement are attached to this Current Report on Form 8-K as Exhibit 99.1 and Exhibit 99.2, respectively, and are incorporated herein by reference.

The information in this Current Report on Form 8-K, including the information set forth in Exhibit 99.1 and Exhibit 99.2, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing

ITEM 9.01 Exhibits.

EXHIBIT NO.		DESCRIPTION

99.1		Press Release dated October 23, 2008 announcing the earnings of Arch Capital Group Ltd. for the three and nine month periods ended September 30, 2008
99.2		Third Quarter 2008 Financial Supplement

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	ARCH CAPITAL GROUP LTD.


Date: October 23, 2008	By:	/s/ W. Preston Hutchings
		Name: W. Preston Hutchings
		Title: Senior Vice President and Chief Investment Officer

EXHIBIT INDEX

EXHIBIT NO.		DESCRIPTION

99.1		Press Release dated October 23, 2008 announcing the earnings of Arch Capital Group Ltd. for the three and nine month periods ended September 30, 2008
99.2		Third Quarter 2008 Financial Supplement