The amortized cost and fair values of securities available for sale and held to maturity were as follows.

						Gross		Gross
				Amortized		Unrealized		Unrealized
December 31, 2013:				Cost		Gains		Losses			Fair Value
				($ in Thousands)
Investment securities available for sale:
	U.S. Treasury securities			$	1,001	$	1	$	-	$	1,002
	Obligations of state and political subdivisions
		(municipal securities)			653,758		23,855		(1,533)		676,080
	Residential mortgage-related securities:
			Government-sponsored enterprise ("GSE")		3,855,467		61,542		(78,579)		3,838,430
			Private-label		3,035		16		(37)		3,014
	GSE commercial mortgage-related securities				673,555		1,764		(27,842)		647,477
	Asset-backed securities⁽¹⁾				23,049		10		-		23,059
	Other securities (debt and equity)				60,711		855		(43)		61,523
			Total investment securities available for sale	$	5,270,576	$	88,043	$	(108,034)	$	5,250,585

Investment securities held to maturity:
	Obligations of state and political subdivisions
		(municipal securities)		$	175,210	$	401	$	(5,722)	$	169,889
			Total investment securities held to maturity	$	175,210	$	401	$	(5,722)	$	169,889

(1) The asset-backed securities position is largely comprised of senior, floating rate, tranches of student loan securities issued by SLM Corp and guaranteed under the Federal Family Education Loan Program.


						Gross		Gross
				Amortized		Unrealized		Unrealized
December 31, 2012:				Cost		Gains		Losses			Fair Value
				($ in Thousands)
Investment securities available for sale:
	U. S. Treasury securities			$	1,003	$	1	$	-	$	1,004
	Obligations of state and political subdivisions
		(municipal securities)			755,644		45,599		(55)		801,188
	Residential mortgage-related securities:
			GSE		3,708,287		93,595		(3,727)		3,798,155
			Private-label		6,002		147		-		6,149
	GSE commercial mortgage-related securities				226,420		2,809		(1,063)		228,166
	Other securities (debt and equity)				90,622		1,549		(75)		92,096
			Total investment securities available for sale	$	4,787,978	$	143,700	$	(4,920)	$	4,926,758

The amortized cost and fair values of investment securities available for sale and held to maturity at December 31, 2013, are shown below. 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.



		Available for Sale				Held to Maturity
($ in Thousands)		Amortized Cost			Fair Value	Amortized Cost			Fair Value
Due in one year or less		$	31,404	$	31,503	$	0	$	0
Due after one year through five years			231,751		240,398		232		233
Due after five years through ten years			429,242		441,137		68,394		66,100
Due after ten years			23,055		25,510		106,584		103,556
	Total debt securities		715,452		738,548		175,210		169,889
Residential mortgage-related securities:
	GSE		3,855,467		3,838,430		-		-
	Private-label		3,035		3,014		-		-
GSE commercial mortgage-related securities			673,555		647,477		-		-
Asset-backed securities			23,049		23,059		-		-
Equity securities			18		57		-		-
	Total investment securities	$	5,270,576	$	5,250,585	$	175,210	$	169,889

For 2013, net investment securities gains of $1 million were primarily attributable to gains on sales of municipal and debt securities. Net investment securities gains of $4 million for 2012, were primarily attributable to gains on sales of equity, mortgage-related, and trust preferred debt securities. Net investment securities losses of $1 million for 2011 were primarily attributable to credit-related other-than-temporary write-downs on the Corporation's holding of various investment securities (including write-downs on trust preferred debt securities and various equity securities).

Total proceeds and gross realized gains and losses from sales and write-downs of investment securities (with other-than-temporary write-downs on securities included in gross losses) for each of the three years ended December 31 were as follows.

		2013		2012		2011
		($ in Thousands)
Gross gains		$	637	$	4,481	$	0
Gross losses			(73)		(220)		(1,112)
	Investment securities gains (losses), net	$	564	$	4,261	$	(1,112)
Proceeds from sales of investment securities			136,152		299,782		176,267

Pledged securities with a carrying value of approximately $2.9 billion and $2.6 billion at December 31, 2013, and December 31, 2012, respectively, were pledged to secure certain deposits, FHLB advances, or for other purposes as required or permitted by law.

The following represents gross unrealized losses and the related fair value of investment securities available for sale and held to maturity, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position, at December 31, 2013.

			Less than 12 months					12 months or more					Total
			Number					Number
			of	Unrealized			Fair	of	Unrealized			Fair	Unrealized			Fair
December 31, 2013			Securities		Losses		Value	Securities		Losses		Value		Losses		Value
			($ in Thousands)
Investment securities available for sale:
	Obligations of state and political
		subdivisions (municipal securities)	113	$	(1,525)	$	47,044	1	$	(8)	$	273	$	(1,533)	$	47,317
	Residential mortgage-related securities:
		GSE	106		(57,393)		1,887,784	15		(21,186)		421,082		(78,579)		2,308,866
		Private-label	2		(37)		2,105	1		-		35		(37)		2,140
	GSE commercial mortgage-related securities		19		(23,854)		443,462	1		(3,988)		45,950		(27,842)		489,412
	Other debt securities		5		(43)		6,452	0		-		-		(43)		6,452
		Total		$	(82,852)	$	2,386,847		$	(25,182)	$	467,340	$	(108,034)	$	2,854,187

Investment securities held to maturity:
	Obligations of state and political
		subdivisions (municipal securities)	298	$	(5,339)	$	124,435	10	$	(383)	$	5,010	$	(5,722)	$	129,445
		Total		$	(5,339)	$	124,435		$	(383)	$	5,010	$	(5,722)	$	129,445

The Corporation reviews the investment securities portfolio on a quarterly basis to monitor its exposure to other-than-temporary impairment. A determination as to whether a security's decline in fair value is other-than-temporary takes into consideration numerous factors and the relative significance of any single factor can vary by security. Some factors the Corporation may consider in the other-than-temporary impairment analysis include, the length of time and extent to which the security has been in an unrealized loss position, changes in security ratings, financial condition and near-term prospects of the issuer, as well as security and industry specific economic conditions. In addition, with regards to its debt securities, the Corporation may also evaluate payment structure, whether there are defaulted payments or expected defaults, prepayment speeds, and the value of any underlying collateral. For certain debt securities in unrealized loss positions, the Corporation prepares cash flow analyses to compare the present value of cash flows expected to be collected from the security with the amortized cost basis of the security.

Based on the Corporation's evaluation, management does not believe any unrealized loss at December 31, 2013, represents an other-than-temporary impairment as these unrealized losses are primarily attributable to changes in interest rates and the current market conditions, and not credit deterioration. The unrealized losses reported for residential mortgage-related securities relate to private-label residential mortgage-related securities as well as residential mortgage-related securities issued by government agencies such as the Federal National Mortgage Association (“FNMA”) and the Federal Home Loan Mortgage Corporation (“FHLMC”). The unrealized losses reported for commercial mortgage related securities relate to government agency mortgage-related securities. The Corporation currently does not intend to sell nor does it believe that it will be required to sell the securities contained in the above unrealized losses table before recovery of their amortized cost basis.

The following is a summary of the credit loss portion of other-than-temporary impairment recognized in earnings on debt securities during 2012 and 2013.

	Private-label
	Mortgage-Related		Trust Preferred
	Securities		Debt Securities			Total
	$ in Thousands
Balance of credit-related other-than-temporary impairment at December 31, 2011	$	(17,558)	$	(10,835)	$	(28,393)
Reduction due to credit impaired securities sold		17,026		4,499		21,525
Balance of credit-related other-than-temporary impairment at December 31, 2012	$	(532)	$	(6,336)	$	(6,868)
Reduction due to credit impaired securities sold		532		57		589
Balance of credit-related other-than-temporary impairment at December 31, 2013	$	0	$	(6,279)	$	(6,279)

For comparative purposes, the following represents gross unrealized losses and the related fair value of investment securities available for sale, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at December 31, 2012.

			Less than 12 months					12 months or more				Total
		Number					Number
		of		Unrealized		Fair	of		Unrealized		Fair		Unrealized		Fair
December 31, 2012		Securities		Losses		Value	Securities	Losses			Value	Losses			Value
			($ in Thousands)
Investment securities available for sale:
Obligations of state and political
	subdivisions (municipal securities)	15	$	(42)	$	5,065	1	$	(13)	$	348	$	(55)	$	5,413
Residential mortgage-related securities:
	GSE	30		(3,727)		892,964	-		-		-		(3,727)		892,964
	Private-label	-		-		-	1		-		50		-		50
GSE commercial mortgage-related securities		2		(1,063)		102,474	-		-		-		(1,063)		102,474
Other securities (debt)		-		-		-	1		(75)		111		(75)		111
	Total		$	(4,832)	$	1,000,503		$	(88)	$	509	$	(4,920)	$	1,001,012

Investment securities held to maturity:
Obligations of state and political
	subdivisions (municipal securities)	56	$	(296)	$	28,265	-	$	-	$	-	$	(296)	$	28,265
	Total		$	(296)	$	28,265		$	-	$	-	$	(296)	$	28,265