The following table summarizes the amortized cost and fair value of the available for sale investment securities portfolio at March 31, 2020 and December 31, 2019 and the corresponding amounts of unrealized gains and losses recognized in accumulated other comprehensive income:

			Gross		Gross
	Amortized		Unrealized		Unrealized
(In Thousands of Dollars)	Cost		Gains		Losses			Fair Value
March 31, 2020
U.S. Treasury and U.S. government sponsored entities	$	3,714	$	126	$	0		$	3,840
State and political subdivisions		273,941		1,171		(7,529	)		267,583
Corporate bonds		3,262		90		(9	)		3,343
Mortgage-backed securities - residential		128,064		5,857		0			133,921
Collateralized mortgage obligations - residential		32,832		458		(239	)		33,051
Small Business Administration		6,265		40		0			6,305
Totals	$	448,078	$	7,742	$	(7,777	)	$	448,043

			Gross		Gross
	Amortized		Unrealized		Unrealized
(In Thousands of Dollars)	Cost		Gains		Losses			Fair Value
December 31, 2019
U.S. Treasury and U.S. government sponsored entities	$	3,773	$	41	$	(3	)	$	3,811
State and political subdivisions		250,905		10,944		(424	)		261,425
Corporate bonds		1,238		22		0			1,260
Mortgage-backed securities - residential		145,886		2,396		(372	)		147,910
Collateralized mortgage obligations - residential		11,459		101		(213	)		11,347
Small Business Administration		6,534		0		(54	)		6,480
Totals	$	419,795	$	13,504	$	(1,066	)	$	432,233

Proceeds from the sale of portfolio securities were $15.1 million during the three month period ended March 31, 2020. Gross gains of $256 thousand along with gross losses of $0 were realized on these sales during the three month period ended March 31, 2020. $99 thousand of realized losses during the three month period were recognized in the income statement for equity securities as of March 31, 2020. Proceeds from the sale of portfolio securities were $9.6 million during the three month period ended March 31, 2019. Gross gains were $22 thousand along with gross losses of $56 thousand during the same three month period ended March 31, 2019. $44 thousand of realized gains during the three month period ended March 31, 2019 were recognized in the income statement for equity securities.

The amortized cost and fair value of the debt securities portfolio are shown by expected maturity. Expected maturities may differ from contractual maturities if issuers 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.

	March 31, 2020
(In Thousands of Dollars)	Amortized Cost		Fair Value
Maturity
Within one year	$	1,185	$	1,186
One to five years		5,493		5,570
Five to ten years		22,426		22,303
Beyond ten years		251,813		245,707
Mortgage-backed, collateralized mortgage obligations and Small Business Administration securities		167,161		173,277
Total	$	448,078	$	448,043

The following table summarizes the available for sale investment securities with unrealized losses at March 31, 2020 and December 31, 2019, aggregated by major security type and length of time in a continuous unrealized loss position.

	Less than 12 Months					12 Months or Longer				Total
	Fair		Unrealized			Fair		Unrealized		Fair		Unrealized
(In Thousands of Dollars)	Value		Loss			Value		Loss		Value		Loss
March 31, 2020

State and political subdivisions	$	170,483	$	(7,529	)	$	0	$	0	$	170,483	$	(7,529	)
Corporate bonds		717		(9	)		0		0		717		(9	)
Collateralized mortgage obligations - residential		10,003		(239	)		0		0		10,003		(239	)
Total	$	181,203	$	(7,777	)	$	0	$	0	$	181,203	$	(7,777	)

	Less than 12 Months					12 Months or Longer					Total
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
(In Thousands of Dollars)	Value		Loss			Value		Loss			Value		Loss
December 31, 2019

U.S. Treasury and U.S. government sponsored entities	$	0	$	0		$	622	$	(3	)	$	622	$	(3	)
State and political subdivisions		30,887		(424	)		0		0			30,887		(424	)
Corporate bonds		0		0			100		0			100		0
Mortgage-backed securities - residential		14,435		(98	)		22,381		(274	)		36,816		(372	)
Collateralized mortgage obligations - residential		1,198		(18	)		7,935		(195	)		9,133		(213	)
Small Business Administration		6,479		(54	)		1		0			6,480		(54	)
Total	$	52,999	$	(594	)	$	31,039	$	(472	)	$	84,038	$	(1,066	)

Management evaluates securities for other-than-temporary impairment (“OTTI”) at least on a quarterly basis, and more frequently when economic or market conditions warrant such an evaluation. Investment securities are generally evaluated for OTTI under ASC Topic 320: Investments - Debt Securities. Consideration is given to the length of time and the extent to which the fair value has been less than cost, the financial condition and near-term prospects of the issuer, whether the market decline was affected by macroeconomic conditions and whether the Company has the intent to sell the debt security or more likely than not will be required to sell the debt security before its anticipated recovery. In analyzing an issuer’s financial condition, the Company may consider whether the securities are issued by the federal government or its agencies, or U.S. government sponsored enterprises, whether downgrades by bond rating agencies have occurred, and the results of reviews of the issuer’s financial condition. The assessment of whether an other-than-temporary decline exists involves a high degree of subjectivity and judgment, and is based on the information available to management at a point in time.

Due to market changes during the first quarter of 2020, securities that had unrealized losses for greater than twelve months at December 31, 2019, appreciated and are in an unrealized gain position at March 31, 2020. Unrealized losses are generally due to changes in interest rates or general market conditions. As of March 31, 2020 and 2019, debt securities had net unrealized losses of $35 thousand and unrealized gains of $769 thousand, respectively. In analyzing an issuer’s financial condition, management considers whether the securities are issued by the federal government or its agencies, whether downgrades by bond rating agencies have occurred, and industry analysts’ reports. Management concluded that the unrealized losses on debt securities were temporary. Due to potential changes in conditions, it is at least reasonably possible that changes in fair values and management’s assessments will occur in the near term and that such changes could materially affect the amounts reported in the Company’s financial statements.

As of March 31, 2020, the Company’s security portfolio consisted of 617 securities, 303 of which were in an unrealized loss position. The majority of the unrealized losses on the Company’s securities are related to its holdings of state and political subdivisions, collateralized mortgage obligations, and corporate bonds securities as discussed below.

Unrealized losses on debt securities issued by state and political subdivisions have not been recognized into income. These securities have maintained their investment grade ratings and management does not have the intent and does not expect to be required to sell these securities before their anticipated recovery. The fair value is expected to recover as the securities approach their maturity date.

All of the Company’s holdings of collateralized mortgage obligations and residential mortgage-backed securities were issued by U.S. government-sponsored entities. Unrealized losses on these securities have not been recognized into income. Because the decline in fair value is attributable to changes in interest rates and illiquidity, and not credit quality, the issues are guaranteed by the issuing entity which the U.S. government has affirmed its commitment to support, and because the Company does not have the intent to sell these residential mortgage-backed securities and it is likely that it will not be required to sell the securities before their anticipated recovery, the Company does not consider these securities to be OTTI.