SECURITIES

Amortized cost and estimated fair value of securities available for sale are as follows (in thousands):



	June 30, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	69,651	$	680	$	—	$	70,331
Mortgage-backed securities, residential	183,682		3,035		—		186,717
Obligations of states and political subdivisions	40,242		1,153		—		41,395
Corporate bonds and notes	748		8		—		756
SBA loan pools	606		4		1		609
Corporate stocks	284		185		—		469
Total	$	295,213	$	5,065	$	1	$	300,277



	December 31, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	99,430	$	752	$	16	$	100,166
Mortgage-backed securities, residential	199,680		427		1,741		198,366
Obligations of states and political subdivisions	43,695		737		6		44,426
Corporate bonds and notes	747		5		—		752
SBA loan pools	643		5		1		647
Corporate stocks	285		178		—		463
Total	$	344,480	$	2,104	$	1,764	$	344,820

Amortized cost and estimated fair value of securities held to maturity are as follows (in thousands):



	June 30, 2016
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Obligations of states and political subdivisions	$	3,518	$	275	$	—	$	3,793
Total	$	3,518	$	275	$	—	$	3,793



	December 31, 2015
	Amortized Cost		Unrealized Gains		Unrealized Losses		Estimated Fair Value
Obligations of states and political subdivisions	$	4,566	$	256	$	—	$	4,822
Total	$	4,566	$	256	$	—	$	4,822

The amortized cost and estimated fair value of debt securities are shown below by expected maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately (in thousands):



	June 30, 2016
	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Within one year	$	42,624	$	42,828	$	1,300	$	1,315
After one, but within five years	58,008		59,164		2,037		2,267
After five, but within ten years	10,009		10,490		181		211
After ten years	—		—		—		—
	110,641		112,482		3,518		3,793
Mortgage-backed securities, residential	183,682		186,717		—		—
SBA loan pools	606		609		—		—
Total	$	294,929	$	299,808	$	3,518	$	3,793

The proceeds from sales and calls of securities resulting in gains or losses for the three months ended June 30, 2016 and 2015 are listed below (in thousands):



	2016		2015
Proceeds	$	—	$	54,268
Gross gains	—		252
Tax expense	—		97

The proceeds from sales and calls of securities resulting in gains or losses for the six months ended June 30, 2016 and 2015 are listed below (in thousands):



	2016		2015
Proceeds	$	15,422	$	54,319
Gross gains	908		302
Tax expense	343		116

The following tables summarize the investment securities available for sale with unrealized losses at June 30, 2016 and December 31, 2015 by aggregated major security type and length of time in a continuous unrealized loss position (in thousands):



	Less than 12 months				12 months or longer				Total
June 30, 2016	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
SBA loan pools	$	—	$	—	$	238	$	1	$	238	$	1
Total temporarily impaired securities	$	—	$	—	$	238	$	1	$	238	$	1



	Less than 12 months				12 months or longer				Total
December 31, 2015	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	15,169	$	16	$	—	$	—	$	15,169	$	16
Mortgage-backed securities, residential	177,058		1,741		—		—		177,058		1,741
Obligations of states and political subdivisions	3,756		4		592		2		4,348		6
SBA loan pools	—		—		251		1		251		1
Total temporarily impaired securities	$	195,983	$	1,761	$	843	$	3	$	196,826	$	1,764

Other-Than-Temporary Impairment

As of June 30, 2016, the Corporation’s unrealized losses in the investment securities portfolio related to SBA loan pools. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because it is not likely that the Corporation will be required to sell these securities before their anticipated recovery, the Corporation does not consider these securities to be other-than-temporarily impaired at June 30, 2016.