The amortized cost, allowance for credit losses, carrying amount, gross unrecognized gains and losses, and the fair value of those investments classified as held-to-maturity at March 31, 2024 are summarized as follows:


	Amortized Cost		Allowance for Credit Losses			Carrying Amount		Gross Unrecognized Gains		Gross Unrecognized Losses			Fair Value
	(in thousands)
States and political subdivisions	$	412,900	$	(37	)	$	412,863	$	2,804	$	(13,871	)	$	401,796
Corporate bonds		48,164		(126	)		48,038		—		(2,078	)		45,960
U.S. agency-based mortgage-backed securities		3,183		—			3,183		19		(150	)		3,052
U.S. Treasury securities and obligations of U.S. government agencies		11,209		—			11,209		14		(379	)		10,844
Asset-backed securities		31		(2	)		29		—		—			29
Totals	$	475,487	$	(165	)	$	475,322	$	2,837	$	(16,478	)	$	461,681

The amortized cost, gross unrealized gains and losses, fair value, and the allowance for credit losses of those investments classified as available-for-sale at March 31, 2024 are summarized as follows:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Allowance for Credit Losses
	(in thousands)
States and political subdivisions	$	122,545	$	260	$	(7,013	)	$	115,792	$	—
Corporate bonds		159,284		1,509		(4,042	)		156,751		—
U.S. agency-based mortgage-backed securities		5,032		—		(502	)		4,530		—
U.S. Treasury securities and obligations of U.S. government agencies		14,830		—		(1,230	)		13,600		—
Totals	$	301,691	$	1,769	$	(12,787	)	$	290,673	$	—

The cost, gross unrealized gains and losses, and the fair value of equity securities at March 31, 2024 are summarized as follows:


	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(in thousands)
Equity securities:
Domestic common stock	$	44,045	$	17,878	$	—	$	61,923
Total equity securities	$	44,045	$	17,878	$	—	$	61,923


	Amortized Cost		Allowance for Credit Losses			Carrying Amount		Gross Unrecognized Gains		Gross Unrecognized Losses			Fair Value
	(in thousands)
States and political subdivisions	$	416,916	$	(38	)	$	416,878	$	4,166	$	(12,074	)	$	408,970
Corporate bonds		52,321		(142	)		52,179		—		(2,231	)		49,948
U.S. agency-based mortgage-backed securities		3,297		—			3,297		25		(123	)		3,199
U.S. Treasury securities and obligations of U.S. government agencies		11,186		—			11,186		26		(273	)		10,939
Asset-backed securities		37		(2	)		35		1		—			36
Totals	$	483,757	$	(182	)	$	483,575	$	4,218	$	(14,701	)	$	473,092

The amortized cost, gross unrealized gains and losses, fair value, and the allowance for credit losses of those investments classified as available-for-sale at December 31, 2023 are summarized as follows:


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Allowance for Credit Losses
	(in thousands)
States and political subdivisions	$	138,031	$	583	$	(6,719	)	$	131,895	$	—
Corporate bonds		168,134		2,105		(3,486	)		166,753		—
U.S. agency-based mortgage-backed securities		5,190		—		(445	)		4,745		—
U.S. Treasury securities and obligations of U.S. government agencies		14,816		—		(1,145	)		13,671		—
Totals	$	326,171	$	2,688	$	(11,795	)	$	317,064	$	—

The cost, gross unrealized gains and losses, and the fair value of equity securities at December 31, 2023 are summarized as follows:


	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(in thousands)
Equity securities:
Domestic common stock	$	44,046	$	13,101	$	—	$	57,147
Total equity securities	$	44,046	$	13,101	$	—	$	57,147

A summary of the carrying amounts and fair value of investments in fixed maturity securities classified as held-to-maturity, by contractual maturity, is as follows:


	March 31, 2024				December 31, 2023
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(in thousands)
Maturity:
Within one year	$	64,898	$	64,232	$	64,129	$	63,703
After one year through five years		126,220		120,555		136,854		131,396
After five years through ten years		116,791		111,569		114,990		110,814
After ten years		164,201		162,244		164,270		163,944
U.S. agency-based mortgage-backed securities		3,183		3,052		3,297		3,199
Asset-backed securities		29		29		35		36
Totals	$	475,322	$	461,681	$	483,575	$	473,092

A summary of the amortized cost and fair value of investments in fixed maturity securities classified as available-for-sale, by contractual maturity, is as follows:


	March 31, 2024				December 31, 2023
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
	(in thousands)
Maturity:
Within one year	$	19,402	$	19,297	$	25,995	$	25,875
After one year through five years		107,593		103,291		106,178		102,201
After five years through ten years		74,338		71,695		82,664		80,911
After ten years		95,326		91,860		106,144		103,332
U.S. agency-based mortgage-backed securities		5,032		4,530		5,190		4,745
Totals	$	301,691	$	290,673	$	326,171	$	317,064

The following table summarizes the fair value and gross unrealized losses on securities classified as available-for-sale, aggregated by major investment category and length of time that the individual securities have been in a continuous unrealized loss position as of March 31, 2024:


	Less Than 12 Months				12 Months or Greater				Total
	Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses		Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses		Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses
	(in thousands)
March 31, 2024
Available-for-Sale
States and political subdivisions	$	61,604	$	4,900	$	25,175	$	2,113	$	86,779	$	7,013
Corporate bonds		79,904		2,613		35,075		1,429		114,979		4,042
U.S. agency-based mortgage-backed securities		4,293		464		237		38		4,530		502
U.S. Treasury securities and obligations of U.S. government agencies		—		—		13,600		1,230		13,600		1,230
Total available-for-sale securities	$	145,801	$	7,977	$	74,087	$	4,810	$	219,888	$	12,787

At March 31, 2024, we held 158 individual fixed maturity securities classified as available-for-sale that were in an unrealized loss position.


	Less Than 12 Months				12 Months or Greater				Total
	Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses		Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses		Fair Value of Investments with Unrealized Losses		Gross Unrealized Losses
	(in thousands)
December 31, 2023
Available-for-Sale
States and political subdivisions	$	14,115	$	111	$	72,358	$	6,608	$	86,473	$	6,719
Corporate bonds		26,178		96		93,538		3,390		119,716		3,486
U.S. agency-based mortgage-backed securities		—		—		4,745		445		4,745		445
U.S. Treasury securities and obligations of U.S. government agencies		—		—		13,672		1,145		13,672		1,145
Total available-for-sale securities	$	40,293	$	207	$	184,313	$	11,588	$	224,606	$	11,795

The following table illustrates the changes in the allowance for credit losses by major security type of the investments classified as held-to-maturity for the quarter ended March 31, 2024.


	States and Political Subdivisions			Corporate Bonds			U.S. Agency -Based Mortgage- Backed Securities		U.S. Treasury Securities and Obligations of U.S. Government Agencies		Asset-Backed Securities		Totals
	(in thousands)
Balance at December 31, 2023	$	38		$	142		$	—	$	—	$	2	$	182
Provision for credit loss benefit		(1	)		(16	)		—		—		—		(17	)
Balance at March 31, 2024	$	37		$	126		$	—	$	—	$	2	$	165

The Company has established an allowance for credit losses on 463 held-to-maturity securities totaling $0.2 million. The majority of those securities were issued by states and political subdivisions (441 securities) and corporate bonds (19 securities).

The Company has no allowance for credit losses on investments classified as available-for-sale for the period ended March 31, 2024.

The credit rating used for held-to-maturity fixed income securities is the rating for each security as published by Moody’s, S&P, and Fitch to determine the probability of default. If there are two ratings, the lower rating is used. If there are three ratings, the median rating is used. If there is one rating, that rating is used. For corporate fixed income securities (given a rating), the probability of default comes from Moody’s annual study of corporate bond defaults published each February. The maximum maturity using the default rate is 20 years (any maturity greater than 20 years will use the 20-year rate). For municipal fixed income securities (given a rating), the probability of default comes from Moody’s annual study of municipal bond defaults published each July/August.

The calculation of the credit loss allowance takes the amortized cost of the fixed income security and assumes default and recovery based on the average recovery rates from the Moody’s default studies. The amortized cost of the security, minus the amount recovered, is the estimated full amount the Company could lose in a default scenario. Then this amount is multiplied by the probability of default to determine the allowance for credit loss. The lower the security is rated, the higher likelihood of default, and therefore a higher allowance for credit loss. The longer to the maturity date of a security, the higher the default risk.

The table below presents the amortized cost of held-to-maturity securities aggregated by credit quality indicator as of March 31, 2024.


	States and Political Subdivisions		Corporate Bonds		U.S. Agency -Based Mortgage- Backed Securities		U.S. Treasury Securities and Obligations of U.S. Government Agencies		Asset-Backed Securities		Totals
	Amortized cost
	(in thousands)
AAA/AA/A ratings	$	409,955	$	18,723	$	3,183	$	11,209	$	18	$	443,088
Baa/BBB ratings		2,945		29,441		—		—		13		32,399
B ratings		—		—		—		—		—		—
Total	$	412,900	$	48,164	$	3,183	$	11,209	$	31	$	475,487

Net realized losses in the quarter ended March 31, 2024 were $0.2 million resulting from the sale of fixed maturity securities classified as available-for-sale. Net realized gains in the quarter ended March 31, 2023 were $0.3 million resulting from the sale of equity and fixed maturity securities classified as available-for-sale.

During the first quarter of 2024, we recognized through income $4.8 million of net unrealized gains on equity securities. During the first quarter of 2023, we recognized through income $1.4 million of net unrealized gains on equity securities.

Investment income is recognized as it is earned. The discount or premium on fixed maturity securities is amortized using the “constant yield” method. Anticipated prepayments, where applicable, are considered when determining the amortization of premiums or discounts. Realized investment gains and losses are determined using the specific identification method.