Our investment portfolio is primarily funded by product premiums from the sale of our TCA F&I products. The amortized cost, gross unrealized gains and losses and estimated fair values of debt securities available-for-sale are as follows:


	As of June 30, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In millions)
Short-term investments	$	10.6	$	—	$	(0.1)	$	10.5
U.S. Treasury	17.1		—		(0.3)		16.9
Municipal	29.5		—		(0.5)		29.1
Corporate	149.2		0.6		(1.8)		148.0
Mortgage and other asset-backed securities	144.6		0.7		(1.6)		143.7




Total investments	$	351.1	$	1.3	$	(4.3)	$	348.1


	As of December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(In millions)
Short-term investments	$	6.3	$	—	$	(0.1)	$	6.2
U.S. Treasury	13.6		0.1		(0.1)		13.5
Municipal	30.1		0.2		(0.2)		30.1
Corporate	131.5		1.6		(0.9)		132.2
Mortgage and other asset-backed securities	150.1		1.6		(0.9)		150.9




Total investments	$	331.6	$	3.5	$	(2.2)	$	332.9

As of June 30, 2024 and December 31, 2023, the Company had $2.7 million and $2.5 million of accrued interest receivable, respectively, which is included in other current assets on the condensed consolidated balance sheets. The Company does not consider accrued interest receivable in the carrying amount of financial assets held at amortized cost basis or in the allowance for credit losses.

A summary of amortized costs and fair value of investments by time to maturity, is as follows:


	As of June 30, 2024
	Amortized Cost		Fair Value
	(In millions)
Due in 1 year or less	$	10.6	$	10.5
Due in 1-5 years	122.9		121.6
Due in 6-10 years	72.9		72.3

Total by maturity	206.5		204.4
Mortgage and other asset-backed securities	144.6		143.7



Total investment securities	$	351.1	$	348.1

There were no gross losses and $0.2 million gross gains realized related to the sale of available-for-sale debt securities carried at fair value for the three months ended June 30, 2024. There were no gross losses and $0.3 million gross gains realized related to the sale of available-for-sale debt securities carried at fair value for the six months ended June 30, 2024.

There were $0.1 million and $0.2 million gross gains realized, respectively, related to the sale of available-for-sale debt securities carried at fair value for the three and six months ended June 30, 2023. There were no gross losses realized related to the sale of available-for-sale debt securities carried at fair value for the three and six months ended June 30, 2023. There were $3.7 million gross gains and $0.9 million gross losses realized, respectively, related to the sale of equity securities carried at fair value for the three and six months ended June 30, 2023.

The following tables summarize the amount of unrealized losses, defined as the amount by which the amortized cost exceeds fair value, and the related fair value of investments with unrealized losses. The investments were segregated into two categories: those that have been in a continuous unrealized loss position for less than 12 months and those that have been in a continuous unrealized loss position for 12 or more months. The reference point for determining how long an investment was in an unrealized loss position was June 30, 2024.


	As of June 30, 2024
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In millions)
Short-term investments	$	—	$	—	$	8.1	$	(0.1)	$	8.1	$	(0.1)
U.S. Treasury	4.0		—		8.2		(0.2)		12.2		(0.3)
Municipal	2.3		—		22.5		(0.5)		24.8		(0.5)
Corporate	22.7		(0.2)		81.9		(1.6)		104.6		(1.8)
Mortgage and other asset-backed securities	22.0		(0.3)		59.5		(1.3)		81.6		(1.6)
Total debt securities	$	51.0	$	(0.5)	$	180.3	$	(3.8)	$	231.3	$	(4.3)


	As of December 31, 2023
	Less than 12 Months				Greater than 12 Months				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In millions)
Short-term investments	$	—	$	—	$	6.0	$	(0.1)	$	6.0	$	(0.1)
U.S. Treasury	3.4		(0.1)		5.0		(0.1)		8.5		(0.1)
Municipal	6.4		(0.1)		10.4		(0.1)		16.8		(0.2)
Corporate	11.4		(0.1)		48.0		(0.8)		59.4		(0.9)
Mortgage and other asset-backed securities	29.8		(0.4)		33.1		(0.5)		62.9		(0.9)
Total debt securities	$	51.1	$	(0.7)	$	102.5	$	(1.6)	$	153.6	$	(2.2)

The Company reviews the investment securities portfolio at the security level on a quarterly basis for potential credit losses, which takes into consideration numerous factors including changes in credit ratings. The decline in fair value identified in the tables above are a result of widening market spreads and not a result of credit quality. Additionally, the Company has determined it has both the intent and ability to hold these investments until the market price recovers or until maturity and does not believe it will be required to sell the securities before maturity. Accordingly, no credit losses were recognized on these securities during the three and six months ended June 30, 2024.