SECURITIES

A summary of the Company's securities portfolio by category and maturity is presented in the following tables.

Securities Portfolio

(Dollar amounts in thousands)



	As of December 31,
	2015									2014
	Amortized Cost		Gross Unrealized					Fair Value		Amortized Cost		Gross Unrealized					Fair Value
	Amortized Cost		Gains		Losses			Fair Value		Amortized Cost		Gains		Losses			Fair Value
Securities Available-for-Sale
U.S. treasury securities	$	17,000	$	15	$	(35	)	$	16,980	$	—	$	—	$	—		$	—
U.S. agency securities	86,461		351		(169		)	86,643		30,297		144		(10		)	30,431
Collateralized mortgage obligations ("CMOs")	695,198		1,072		(9,085		)	687,185		538,882		2,256		(6,982		)	534,156
Other mortgage-backed securities ("MBSs")	152,481		1,920		(871		)	153,530		155,443		4,632		(310		)	159,765
Municipal securities	321,437		6,443		(310		)	327,570		414,255		10,583		(1,018		)	423,820
Trust preferred collateralized debt obligations ("CDOs")	48,287		34		(16,792		)	31,529		48,502		152		(14,880		)	33,774
Corporate debt securities	—		—		—			—		1,719		83		—			1,802
Equity securities	3,282		86		(169		)	3,199		3,224		72		(35		)	3,261
Total securities available-for-sale	$	1,324,146	$	9,921	$	(27,431	)	$	1,306,636	$	1,192,322	$	17,922	$	(23,235	)	$	1,187,009
Securities Held-to-Maturity
Municipal securities	$	23,152	$	—	$	(3,098	)	$	20,054	$	26,555	$	1,115	$	—		$	27,670
Trading Securities								$	16,894								$	17,460

Remaining Contractual Maturity of Securities

(Dollar amounts in thousands)



	As of December 31, 2015
	Available-for-Sale				Held-to-Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	95,201	$	93,096	$	2,092	$	1,812
After one year to five years	272,169		266,151		8,809		7,630
After five years to ten years	57,528		56,256		4,184		3,624
After ten years	48,287		47,219		8,067		6,988
Securities that do not have a single contractual maturity date	850,961		843,914		—		—
Total	$	1,324,146	$	1,306,636	$	23,152	$	20,054

The carrying value of securities available-for-sale that were pledged to secure deposits or for other purposes as permitted or required by law totaled $856.9 million as of December 31, 2015 and $779.4 million as of December 31, 2014. No securities held-to-maturity were pledged as of December 31, 2015 or 2014.

Excluding securities issued or backed by the U.S. government and its agencies and U.S. government-sponsored enterprises, there were no investments in securities from one issuer that exceeded 10% of total stockholders' equity as of December 31, 2015 or 2014.

During the years ended December 31, 2015, 2014, and 2013 there were no material gross trading gains (losses). The following table presents net realized gains on securities available-for-sale.

Securities Available-for-Sale Gains (Losses)

(Dollar amounts in thousands)



	Years Ended December 31,
	2015			2014			2013
Gains (losses) on sales of securities:
Gross realized gains	$	2,519		$	8,188		$	34,572
Gross realized losses	(146		)	(63		)	—
Net realized gains on sales of securities	2,373			8,125			34,572
Non-cash impairment charges:
OTTI	—			(28		)	(408		)
Net realized gains	$	2,373		$	8,097		$	34,164

During 2015, net securities gains primarily consisted of sales of MBSs at gains of $1.9 million and sales of CMOs, municipal securities, and other investments at net gains of $521,000. Net securities gains consisted of the sale of a non-accrual CDO at a gain of $3.5 million and other investments at gains totaling $4.6 million during 2014. The Company sold its investment in an equity security during 2013, which resulted in a $34.0 million gain.

Accounting guidance requires that the credit portion of an OTTI charge be recognized through income. If a decline in fair value below carrying value is not attributable to credit deterioration and the Company does not intend to sell the security or believe it would not be more likely than not required to sell the security prior to recovery, the Company records the non-credit related portion of the decline in fair value in other comprehensive (loss) income.

The following table presents a rollforward of life-to-date OTTI recognized in earnings related to all securities available-for-sale held by the Company for the years ended December 31, 2015, 2014, and 2013. The majority of the beginning and ending balance of OTTI relates to CDOs currently held by the Company.

Changes in OTTI Recognized in Earnings

(Dollar amounts in thousands)



	Years Ended December 31,
	2015			2014			2013
Beginning balance	$	23,880		$	32,422		$	38,803
OTTI included in earnings ⁽¹⁾:
Losses on securities that previously had OTTI	—			28			—
Losses on securities that did not previously have OTTI	—			—			408
Reduction for securities sales ⁽²⁾	(171		)	(8,570		)	(6,789		)
Ending balance	$	23,709		$	23,880		$	32,422


⁽¹⁾	Included in net securities gains in the Consolidated Statements of Income.


⁽²⁾	These reductions were driven by the sale of one CMO with a carrying value of $1.3 million during the year ended December 31, 2015, one CDO with a carrying value of $1.3 million during the year ended December 31, 2014, and one CDO with a carrying value of zero during the year ended December 31, 2013.

The following table presents the aggregate amount of unrealized losses and the aggregate related fair values of securities with unrealized losses as of December 31, 2015 and 2014.

Securities in an Unrealized Loss Position

(Dollar amounts in thousands)



		Less Than 12 Months				Greater Than 12 Months				Total
	Number of Securities	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
As of December 31, 2015
Securities Available-for-Sale:
U.S. treasury securities	4	$	7,946	$	35	$	—	$	—	$	7,946	$	35
U.S. agency securities	10	30,620		169		—		—		30,620		169
CMOs	133	309,787		3,110		257,362		5,975		567,149		9,085
MBSs	27	63,028		427		31,980		444		95,008		871
Municipal securities	68	8,135		65		24,227		245		32,362		310
CDOs	8	8,034		971		21,642		15,821		29,676		16,792
Equity securities	2	485		120		2,305		49		2,790		169
Total	252	$	428,035	$	4,897	$	337,516	$	22,534	$	765,551	$	27,431
Securities Held-to-Maturity:
Municipal securities	19	$	20,054	$	3,098	$	—	$	—	$	20,054	$	3,098

As of December 31, 2014
Securities Available-for-Sale:
U.S. agency securities	1	$	1,943	$	10	$	—	$	—	$	1,943	$	10
CMOs	87	61,321		559		284,327		6,423		345,648		6,982
MBSs	11	1,113		1		39,043		309		40,156		310
Municipal securities	91	1,317		9		53,987		1,009		55,304		1,018
CDOs	4	—		—		22,791		14,880		22,791		14,880
Equity securities	1	—		—		2,270		35		2,270		35
Total	195	$	65,694	$	579	$	402,418	$	22,656	$	468,112	$	23,235

Substantially all of the Company's CMOs and other MBSs are either backed by U.S. government-owned agencies or issued by U.S. government-sponsored enterprises. Municipal securities are issued by municipal authorities, and the majority are supported by third party insurance or some other form of credit enhancement. Management does not believe any of these securities with unrealized losses as of December 31, 2015 represent OTTI related to credit deterioration. These unrealized losses are attributed to changes in interest rates and temporary market movements. The Company does not intend to sell these securities and it is not more likely than not that the Company will be required to sell them before recovery of their amortized cost basis, which may be at maturity.

The unrealized losses on CDOs as of December 31, 2015 reflect changes in market activity for these securities. Management does not believe these unrealized losses represent OTTI related to credit deterioration. In addition, the Company does not intend to sell the CDOs with unrealized losses within a short period of time, and the Company does not believe it is more likely than not that it will be required to sell them before recovery of their amortized cost basis, which may be at maturity. Significant judgment is required to calculate the fair value of the CDOs, all of which are pooled. For a detailed discussion of the CDO valuation methodology, see Note 22, "Fair Value."