5. Securities

Securities Available for Sale

This table provides detailed information about securities available for sale at March 31, 2013 and December 31, 2012 (in thousands):


March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	121,777	$	1,260	$	(216	)	$	122,821
U.S. Agencies		1,042,955		6,136		(119	)		1,048,972
Mortgage-backed		3,218,547		57,084		(4,913	)		3,270,718
State and political subdivisions		1,928,957		45,193		(4,214	)		1,969,936
Corporates		427,500		2,378		(741	)		429,137
Commercial Paper		—		—		—			—

Total	$	6,739,736	$	112,051	$	(10,203	)	$	6,841,584


December 31, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury	$	116,856	$	1,166	$	(171	)	$	117,851
U.S. Agencies		1,019,640		6,597		(122	)		1,026,115
Mortgage-backed		3,480,006		78,600		(2,413	)		3,556,193
State and political subdivisions		1,842,715		51,341		(1,372	)		1,892,684
Corporates		337,706		1,945		(764	)		338,887
Commercial Paper		5,733		—		—			5,733

Total	$	6,802,656	$	139,649	$	(4,842	)	$	6,937,463

The following table presents contractual maturity information for securities available for sale at March 31, 2013 (in thousands):


	Amortized Cost		Fair Value
Due in 1 year or less	$	569,017	$	571,721
Due after 1 year through 5 years		2,020,200		2,048,453
Due after 5 years through 10 years		753,872		773,932
Due after 10 years		178,100		176,760

Total		3,521,189		3,570,866
Mortgage-backed securities		3,218,547		3,270,718

Total securities available for sale	$	6,739,736	$	6,841,584

Securities may be disposed of before contractual maturities due to sales by the Company or because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

For the three months ended March 31, 2013, proceeds from the sales of securities available for sale were $333.9 million compared to $775.7 million for the same period in 2012. Securities transactions resulted in gross realized gains of $5.9 million and $16.9 million for the three months ended March 31, 2013 and 2012. The gross realized losses for the three months ended March 31, 2013 and 2012 were $37 thousand and $342 thousand, respectively.

Trading Securities

The net unrealized gains on trading securities at March 31, 2013 and March 31, 2012 were $0.2 million and $1.6 million, respectively, and were included in trading and investment banking income on the consolidated statements of income.

Securities Held to Maturity

The table below provides detailed information for securities held to maturity at March 31, 2013 and December 31, 2012 (in thousands):


March 31, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
State and political subdivisions	$	129,498	$	13,033	$	—	$	142,531

December 31, 2012
State and political subdivisions	$	114,756	$	14,739	$	—	$	129,495

The following table presents contractual maturity information for securities held to maturity at March 31, 2013 (in thousands):


	Amortized Cost		Fair Value
Due in 1 year or less	$	1,466	$	1,614
Due after 1 year through 5 years		30,829		33,932
Due after 5 years through 10 years		31,884		35,092
Due after 10 years		65,319		71,893

Total securities held to maturity	$	129,498	$	142,531

Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

There were no sales of securities held to maturity during the first three months of 2013 or 2012.

Securities available for sale and held to maturity with a market value of $5.3 billion at March 31, 2013, and $5.9 billion at December 31, 2012, were pledged to secure U.S. Government deposits, other public deposits, certain trust deposits as required by law, and other potential borrowings.

The following table shows the Company’s available for sale investments’ gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2013 and December 31, 2012 (in thousands).


March 31, 2013	Less than 12 months					12 months or more					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury	$	19,765	$	(216	)	$	—	$	—		$	19,765	$	(216	)
U.S. Agencies		195,815		(119	)		—		—			195,815		(119	)
Mortgage-backed		583,894		(4,913	)		—		—			583,894		(4,913	)
State and political subdivisions		289,738		(4,160	)		5,540		(54	)		295,278		(4,214	)
Corporates		153,982		(741	)		—		—			153,982		(741	)
Commercial Paper		—		—			—		—			—		—

Total temporarily - impaired debt securities available for sale	$	1,243,194	$	(10,149	)	$	5,540	$	(54	)	$	1,248,734	$	(10,203	)


December 31, 2012	Less than 12 months					12 months or more					Total
Description of Securities	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury	$	29,747	$	(171	)	$	—	$	—		$	29,747	$	(171	)
U.S. Agencies		295,747		(122	)		—		—			295,747		(122	)
Mortgage-backed		398,384		(2,413	)		—		—			398,384		(2,413	)
State and political subdivisions		132,951		(1,358	)		2,604		(14	)		135,555		(1,372	)
Corporates		178,564		(764	)		—		—			178,564		(764	)
Commercial Paper		5,733		—			—		—			5,733		—

Total temporarily-impaired debt securities available for sale	$	1,041,126	$	(4,828	)	$	2,604	$	(14	)	$	1,043,730	$	(4,842	)

The unrealized losses in the Company’s investments in direct obligations of U.S. treasury obligations, U.S. government agencies, federal agency mortgage-backed securities, municipal securities, and corporates were caused by changes in interest rates. The Company does not have the intent to sell these securities and does not believe it is more likely than not that the Company will be required to sell these securities before a recovery of fair value. The Company expects to recover its cost basis in the securities and does not consider these investments to be other-than-temporarily impaired at March 31, 2013.