SECURITIES

Amortized cost and estimated fair value of securities available for sale at December 31, 2018 and 2017 are as follows (in thousands):



	2018				2017
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	5,489	$	5,472	$	15,492	$	15,491
Mortgage-backed securities, residential	189,111		183,192		224,939		219,909
Obligations of states and political subdivisions	44,390		44,152		52,928		53,132
Corporate bonds and notes	249		247		249		251
SBA loan pools	9,257		9,195		4,339		4,308
Total	$	248,496	$	242,258	$	297,947	$	293,091

Gross unrealized gains and losses on securities available for sale at December 31, 2018 and 2017, were as follows (in thousands):



	2018				2017
	Unrealized Gains		Unrealized Losses		Unrealized Gains		Unrealized Losses
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	10	$	27	$	20	$	21
Mortgage-backed securities, residential	146		6,065		136		5,166
Obligations of states and political subdivisions	70		308		355		151
Corporate bonds and notes	—		2		2		—
SBA loan pools	—		62		1		32
Total	$	226	$	6,464	$	514	$	5,370

The amortized cost and estimated fair value of debt securities available for sale are shown below by contractual 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):



	December 31, 2018
	Amortized Cost		Fair Value
Within one year	$	11,603	$	11,578
After one, but within five years	11,808		11,754
After five, but within ten years	10,876		10,829
After ten years	15,841		15,710
Mortgage-backed securities, residential	189,111		183,192
SBA loan pools	9,257		9,195
Total	$	248,496	$	242,258

Actual maturities may differ from contractual maturities above because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.

The proceeds from sales and calls of securities resulting in gains or losses are listed below (in thousands):



	2018		2017		2016
Proceeds	$	—	$	5,576	$	40,413
Gross gains	$	—	$	109	$	989
Gross losses	$	—	$	—	$	(2	)
Tax expense	$	—	$	41	$	373

Amortized cost and estimated fair value of securities held to maturity at December 31, 2018 and 2017 are as follows (in thousands):



	2018				2017
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Obligations of states and political subdivisions	$	3,020	$	3,020	$	1,946	$	1,946
Time deposits with other financial institutions	1,855		1,838		1,835		1,830
	$	4,875	$	4,858	$	3,781	$	3,776

Gross unrealized gains and losses on securities held to maturity at December 31, 2018 and 2017, were as follows (in thousands):



	2018				2017
	Unrealized Gains		Unrealized Losses		Unrealized Gains		Unrealized Losses
Obligations of states and political subdivisions	$	—	$	—	$	—	$	—
Time deposits with other financial institutions	—		17		—		5
Total	$	—	$	17	$	—	$	5

There were no sales of securities held to maturity in 2018 or 2017.

The contractual maturity of securities held to maturity is as follows at December 31, 2018 (in thousands):



	December 31, 2018
	Amortized Cost		Fair Value
Within one year	$	2,783	$	2,777
After one, but within five years	2,092		2,081
After five, but within ten years	—		—
After ten years	—		—
Total	$	4,875	$	4,858

The following table summarizes the investment securities available for sale with unrealized losses at December 31, 2018 and December 31, 2017 by aggregated major security type and length of time in a continuous unrealized position (in thousands):



	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
2018	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	—	$	—	$	4,969	$	27	$	4,969	$	27
Mortgage-backed securities, residential	—		—		171,481		6,065		171,481		6,065
Obligations of states and political subdivisions	10,868		38		21,345		270		32,213		308
Corporate bonds and notes	247		2		—		—		247		2
SBA loan pools	5,985		17		3,210		45		9,195		62
Total temporarily impaired securities	$	17,100	$	57	$	201,005	$	6,407	$	218,105	$	6,464



	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
2017	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Obligations of U.S. Government and U.S. Government sponsored enterprises	$	14,982	$	21	$	—	$	—	$	14,982	$	21
Mortgage-backed securities, residential	83,562		1,013		131,165		$	4,153	214,727		5,166
Obligations of states and political subdivisions	20,526		133		271		18		20,797		151
SBA loan pools	3,937		32		—		—		3,937		32
Total temporarily impaired securities	$	123,007	$	1,199	$	131,436	$	4,171	$	254,443	$	5,370

Other-Than-Temporary-Impairment

As of December 31, 2018, the majority of the Corporation’s unrealized losses in the investment securities portfolio related to mortgage-backed securities. At December 31, 2018, all of the unrealized losses related to mortgage-backed securities were issued by U.S. government sponsored entities, Fannie Mae and Freddie Mac. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Corporation does not have the intent to sell these securities and it is not likely that it 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 December 31, 2018.

The Corporation's unrealized losses on securities held to maturity related to certificates of deposits. At December 31, 2018, all of the unrealized losses related to certificates of deposit within other financial institutions and were under the FDIC insurance limit of $250,000. Because the decline in fair value is attributable to changes in interest rates and not credit quality, and because the Corporation does not have the intent to sell these securities and it is not likely that it will be required to see these securities before their anticipated recovery, the Corporation does not consider these securities to be other-than-temporarily impaired at December 31, 2018.

Pledged Securities

The fair value of securities pledged to secure public funds on deposit or for other purposes as required by law was $212.7 million at December 31, 2018 and $231.6 million at December 31, 2017.

The table below shows the securities pledged to secure securities sold under agreements to repurchase at December 31, 2018 and 2017 (in thousands):



	2018				2017
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Mortgage-backed securities, residential	$	—	$	—	$	12,082	$	11,798
Total	$	—	$	—	$	12,082	$	11,798

Concentrations

There are no securities of a single issuer (other than securities of U.S. Government sponsored enterprises) that exceed 10% of shareholders' equity at December 31, 2018 or 2017.

Equity Method Investments

The Corporation has an equity investment in Cephas Capital Partners, L.P. This small business investment company was established for the purpose of providing financing to small businesses in market areas served by the Corporation, including minority-owned small businesses and those that are anticipated to create jobs for the low to moderate income levels in the targeted areas. As of both December 31, 2018 and 2017, this investment totaled $0.4 million, is included in other assets, and is accounted for under the equity method of accounting.