Investments in Fixed Maturity Securities

At December 31, 2011 and 2010, investments in fixed maturity securities were as follows:



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Carrying Value
December 31, 2011
Held to maturity:
State and municipal	$	74,354	$	12,546	$	—		$	86,900	$	74,354
Residential mortgage-backed securities	35,759		5,610		—			41,369		35,759
Corporate	4,996		717		—			5,713		4,996
Total held to maturity	115,109		18,873		—			133,982		115,109
Available for sale:
U.S. government and government agency	906,924		69,920		(351		)	976,493		976,493
State and municipal	5,031,275		308,345		(16,550		)	5,323,070		5,323,070
Mortgage-backed securities:
Residential(1)	1,416,427		75,635		(15,894		)	1,476,168		1,476,168
Commercial	105,383		4,054		(1,018		)	108,419		108,419
Corporate	2,328,200		132,311		(36,087		)	2,424,424		2,424,424
Foreign	850,838		42,165		(4,649		)	888,354		888,354
Total available for sale	10,639,047		632,430		(74,549		)	11,196,928		11,196,928
Total investment in fixed maturity securities	$	10,754,156	$	651,303	$	(74,549	)	$	11,330,910	$	11,312,037



(Dollars in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Carrying Value
December 31, 2010
Held to maturity:
State and municipal	$	71,998	$	3,440	$	(1,129	)	$	74,309	$	71,998
Residential mortgage-backed securities	39,002		3,667		—			42,669		39,002
Corporate	4,995		185		—			5,180		4,995
Total held to maturity	115,995		7,292		(1,129		)	122,158		115,995
Available for sale:
U.S. government and government agency	1,289,669		58,658		(452		)	1,347,875		1,347,875
State and municipal	5,302,513		203,221		(44,288		)	5,461,446		5,461,446
Mortgage-backed securities:
Residential(1)	1,319,289		52,165		(13,278		)	1,358,176		1,358,176
Commercial	57,057		2,207		(5,594		)	53,670		53,670
Corporate	2,055,513		93,789		(29,379		)	2,119,923		2,119,923
Foreign	713,157		39,800		(888		)	752,069		752,069
Total available for sale	10,737,198		449,840		(93,879		)	11,093,159		11,093,159
Total investment in fixed maturity securities	$	10,853,193	$	457,132	$	(95,008	)	$	11,215,317	$	11,209,154

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(1)	Gross unrealized losses for mortgage-backed securities include $7,668,000 and $4,064,000, as of December 31, 2011 and 2010, respectively, related to the non-credit portion of OTTI recognized in other comprehensive income.

The amortized cost and fair value of fixed maturity securities at December 31, 2011, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because certain issuers may have the right to call or prepay obligations:



(Dollars in thousands)	Amortized Cost		Fair Value
Due in one year or less	$	731,638	$	742,334
Due after one year through five years	3,057,341		3,202,556
Due after five years through ten years	2,646,432		2,864,395
Due after ten years	2,761,176		2,895,669
Mortgage-backed securities	1,557,569		1,625,956
Total	$	10,754,156	$	11,330,910

At December 31, 2011 and 2010, there were no investments, other than investments in United States government and government agency securities, which exceeded 10% of common stockholders’ equity. At December 31, 2011, investments with a carrying value of $912 million were on deposit in custodial or trust accounts, of which $664 million was on deposit with state insurance departments, $155 million was on deposit in support of the Company’s underwriting activities at Lloyd’s, $64 million was on deposit as security for reinsurance clients and $29 million was on deposit as security for letters of credit issued in support of the Company’s reinsurance operations.