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Exhibit 12

Arch Capital Group Ltd. and Subsidiaries
Computation of Ratio of Earnings to Fixed Charges and Preference Dividends
(in thousands, except ratios)

		Years Ended December 31,
		2008		2007			2006			2005		2004
Income before income taxes		$	304,505	$	873,544		$	739,893		$	285,435	$	343,127
	Equity in net loss (income) of investees		166,326		(8,877	)		(3,102	)		0		(1,211	)
	Fixed charges		29,673		27,032			26,386			26,204		22,103
Income available for fixed charges		$	500,504	$	891,699		$	763,177		$	311,639	$	364,019
Fixed charges:
	Interest and amortization on indebtedness		23,838		22,093			22,090			22,504		17,970
	Estimate of interest component within rental expense net of sublease (income) (1)		5,835		4,939			4,296			3,700		4,133
Total fixed charges			29,673		27,032			26,386			26,204		22,103
Preference dividends			25,844		25,844			20,655			—		—
Total fixed charges and preference dividends			55,517		52,876			47,041			26,204		22,103
Ratio of earnings to fixed charges			16.9		33.0			28.9			11.9		16.5
Ratio of earnings to fixed charges and preference dividends			9.0		16.9			16.2			11.9		16.5

(1)

Represents a reasonable approximation of the interest cost component of rental expense net of sublease (income) incurred by the Company.

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Exhibit 12

Arch Capital Group Ltd. and Subsidiaries Computation of Ratio of Earnings to Fixed Charges and Preference Dividends (in thousands, except ratios)