The tables below provide the amortized cost, unrealized gains and losses, and fair values of debt securities summarized by major category (dollars in thousands):

Amortized cost and fair value of debt securities, by contractual maturity or pre-refunded date, are shown below. Mortgages underlying mortgage-backed securities and asset-backed securities may be called or prepaid; therefore, actual maturities could differ from the contractual maturities. All mortgage-backed securities were issued by U.S. government corporations and agencies (dollars in thousands):

Realized gains and losses related to sales and calls of debt securities available for sale are summarized as follows (dollars in thousands):

(1)

Net gains (losses) on sales of securities reported in the unaudited Consolidated Statements of Income include sales of equity securities, excluded in this table.

Debt securities with carrying amounts of $685.2 million on June 30, 2022, and $708.9 million on December 31, 2021, were pledged as collateral for public deposits, securities sold under agreements to repurchase, and for other purposes as required.

Debt securities in an unrealized loss position

The following information pertains to debt securities with gross unrealized losses, aggregated by investment category and the length of time that individual securities have been in a continuous loss position (dollars in thousands):


	As of June 30, 2022
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
Debt securities available for sale
U.S. Treasury securities	$	21,976	$	(154)	$	124,094	$	(3,929)	$	146,070	$	(4,083)
Obligations of U.S. government corporations and agencies		17,078		(81)		—		—		17,078		(81)
Obligations of states and political subdivisions		192,737		(16,868)		11,056		(1,520)		203,793		(18,388)
Asset-backed securities		465,293		(22,632)		2,835		(171)		468,128		(22,803)
Commercial mortgage-backed securities		91,564		(6,560)		6,798		(662)		98,362		(7,222)
Residential mortgage-backed securities		1,035,112		(96,222)		399,554		(62,445)		1,434,666		(158,667)
Corporate debt securities		178,170		(14,790)		83,656		(6,519)		261,826		(21,309)
Debt securities available for sale with gross unrealized losses	$	2,001,930	$	(157,307)	$	627,993	$	(75,246)	$	2,629,923	$	(232,553)

Debt securities held to maturity
Commercial mortgage-backed securities	$	241,060	$	(19,840)	$	213,177	$	(18,847)	$	454,237	$	(38,687)
Residential mortgage-backed securities		382,897		(33,909)		39,603		(3,678)		422,500		(37,587)
Debt securities held to maturity with gross unrealized losses	$	623,957	$	(53,749)	$	252,780	$	(22,525)	$	876,737	$	(76,274)


	As of December 31, 2021
	Less than 12 months				12 months or more				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
Debt securities available for sale
U.S. Treasury securities	$	163,653	$	(1,047)	$	—	$	—	$	163,653	$	(1,047)
Obligations of states and political subdivisions		92,680		(1,493)		—		—		92,680		(1,493)
Asset-backed securities		89,983		(164)		—		—		89,983		(164)
Commercial mortgage-backed securities		389,078		(10,186)		85,905		(3,580)		474,983		(13,766)
Residential mortgage-backed securities		1,700,187		(33,453)		20,538		(1,227)		1,720,725		(34,680)
Corporate debt securities		241,153		(3,504)		—		—		241,153		(3,504)
Debt securities available for sale with gross unrealized losses	$	2,676,734	$	(49,847)	$	106,443	$	(4,807)	$	2,783,177	$	(54,654)

Additional information about debt securities in an unrealized loss position is presented in the tables below (dollars in thousands):


	As of June 30, 2022
	Available for Sale			Held to Maturity			Total
Debt securities with gross unrealized losses, fair value	$	2,629,923		$	876,737		$	3,506,660
Gross unrealized losses on debt securities	$	232,553		$	76,274		$	308,827
Ratio of gross unrealized losses to debt securities with gross unrealized losses		8.8	%		8.7	%		8.8	%

Count of debt securities		1,177			55			1,232
Count of debt securities in an unrealized loss position		881			55			936


	As of December 31, 2021
	Available for Sale			Held to Maturity		Total
Debt securities with gross unrealized losses, fair value	$	2,783,177		$	—	$	2,783,177
Gross unrealized losses on debt securities	$	54,654		$	—	$	54,654
Ratio of gross unrealized losses to debt securities with gross unrealized losses		2.0	%		—		2.0	%

Count of debt securities		1,252			—		1,252
Count of debt securities in an unrealized loss position		373			—		373

Unrealized losses were related to changes in market interest rates and market conditions that do not represent credit-related impairments. The Company does not intend to sell securities that are in an unrealized loss position, and it is more likely than not that the Company will recover the amortized cost prior to being required to sell the debt securities. Full collection of the amounts due according to the contractual terms of the debt securities is expected; therefore, no ACL was recorded in relation to debt securities, and the impairment related to noncredit factors is recognized in AOCI, net of applicable taxes. As of June 30, 2022, the Company did not hold general obligation bonds of any single issuer, the aggregate of which exceeded 10% of the Company’s stockholders’ equity.