
($ in millions)	Year Ended December 31,
	2023		2022		2021
Fixed maturity securities	$	269.2	$	247.2	$	235.6
Equity securities	6.5		9.0		5.3
Limited partnership interests	59.1		40.5		79.0
Short-term and other investments	17.2		11.2		11.6
Investment expenses	(12.1)		(10.5)		(10.1)
Net investment income - investment portfolio	339.9		297.4		321.4
Investment income - deposit asset on reinsurance	104.9		103.5		101.1
Total net investment income	$	444.8	$	400.9	$	422.5

The Company, from time to time, sells fixed maturity securities subsequent to the reporting date but prior to the issuance of the financial statements that were in an unrealized loss position but no credit loss was recognized and there was no intent to sell the securities at the reporting date. Such sales are due to issuer-specific events occurring subsequent to the reporting date that result in a change in the Company's intent to sell a fixed maturity security. The types of events that may result in a sale include significant changes in the economic facts and circumstances related to the invested asset, significant unforeseen changes in liquidity needs, or changes in the Company's investment strategy.


($ in millions)	Year Ended December 31,
	2023		2022		2021
Credit loss impairments	$	(0.4)	$	(3.1)	$	(8.1)
Intent-to-sell impairments	(6.7)		(7.6)		(2.3)
Total impairments	(7.1)		(10.7)		(10.4)
Sales and other, net	(25.0)		(17.8)		4.3
Change in fair value - equity securities	7.9		(33.2)		(2.3)
Change in fair value and losses realized on settlements - derivatives	0.2		5.2		(2.6)
Net investment losses	$	(24.0)	$	(56.5)	$	(11.0)

The following table presents changes in the allowance for credit loss impairments on fixed maturity securities classified as available for sale for the category of other asset-backed securities (no other categories of fixed maturity securities have an allowance for credit loss impairments):


($ in millions)	Year Ended December 31,
	2023		2022		2021
Beginning balance	$	1.2	$	7.7	$	—
Credit losses on fixed maturity securities for which credit losses were not previously reported	—		—		8.1
Net increases (decreases) related to credit losses previously reported	—		3.1		—
Reduction of credit allowances related to sales	—		(9.2)		—
Write-offs	—		(0.4)		(0.4)
Ending balance	$	1.2	$	1.2	$	7.7


($ in millions)	Amortized Cost, net		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
December 31, 2023
Fixed maturity securities
U.S. Government and federally sponsored agency obligations:
Mortgage-backed securities	$	713.4	$	4.4	$	64.6	$	653.2
Other, including U.S. Treasury securities	450.8		0.8		62.8		388.8
Municipal bonds	1,333.4		28.6		91.9		1,270.1
Foreign government bonds	23.1		—		1.0		22.1
Corporate bonds	1,969.9		23.1		220.3		1,772.7
Other asset-backed securities	1,162.3		6.0		39.9		1,128.4
Totals	$	5,652.9	$	62.9	$	480.5	$	5,235.3

December 31, 2022
Fixed maturity securities
U.S. Government and federally sponsored agency obligations:
Mortgage-backed securities	$	638.2	$	1.3	$	69.1	$	570.4
Other, including U.S. Treasury securities	410.0		0.5		67.8		342.7
Municipal bonds	1,380.9		16.9		128.1		1,269.7
Foreign government bonds	35.1		—		1.6		33.5
Corporate bonds	2,161.2		12.7		272.2		1,901.7
Other asset-backed securities	1,131.5		3.6		68.1		1,067.0
Totals	$	5,756.9	$	35.0	$	606.9	$	5,185.0

The following table presents the fair value and gross unrealized losses for fixed maturity securities in an unrealized loss position as of December 31, 2023 and 2022. The Company views the decrease in fair value of all fixed maturity securities with unrealized losses as of December 31, 2023 as due to factors other than a credit loss. As of December 31, 2023, the Company has not made the decision to sell and it is more likely than not the Company will not be required to sell the fixed maturity securities with unrealized losses before a recovery of the amortized cost basis. In reaching our conclusion that an allowance for credit is unnecessary, we considered the factors described in the Application of Critical Accounting Estimates - Evaluation of Credit Loss Impairments for Fixed Maturity Securities. The performance of fixed maturity securities has been impacted by the change in interest rates, specifically interest rates being at relatively high levels compared to interest rates at the time of acquisition of the securities. Following significant increases in interest rates throughout 2022, driven mostly by increases in risk-free rates, rates stabilized during 2023 but remain at elevated levels. In consideration of the factors, we expect to receive cash flows sufficient to recover the entire amortized cost basis of the securities in the following table.


($ in millions)	12 months or less					More than 12 months					Total
	Fair Value			Gross Unrealized Losses		Fair Value			Gross Unrealized Losses		Fair Value			Gross Unrealized Losses
December 31, 2023
Fixed maturity securities
U.S. Government and federally sponsored agency obligations:
Mortgage-backed securities	$	45.3		$	0.8	$	458.5		$	63.8	$	503.8		$	64.6
Other	39.5			0.4		288.0			62.4		327.5			62.8
Municipal bonds	64.5			0.9		724.6			91.0		789.1			91.9
Foreign government bonds	1.5			—		20.6			1.0		22.1			1.0
Corporate bonds	195.0			25.4		1,171.3			194.9		1,366.3			220.3
Other asset-backed securities	133.4			0.8		752.5			39.1		885.9			39.9
Total	$	479.2		$	28.3	$	3,415.5		$	452.2	$	3,894.7		$	480.5

Number of positions with a gross unrealized loss	195					2,305					2,500
Fair value as a percentage of total fixed maturities securities fair value	9.2		%			65.2		%			74.4		%

December 31, 2022
Fixed maturity securities
U.S. Government and federally sponsored agency obligations:
Mortgage-backed securities	$	458.3		$	54.4	$	52.6		$	14.7	$	510.9		$	69.1
Other	242.7			34.1		65.8			33.7		308.5			67.8
Municipal bonds	911.6			113.7		42.2			14.4		953.8			128.1
Foreign government bonds	32.7			1.4		0.4			0.2		33.1			1.6
Corporate bonds	1,345.0			221.1		148.9			51.1		1,493.9			272.2
Other asset-backed securities	543.4			37.1		424.3			31.0		967.7			68.1
Total	$	3,533.7		$	461.8	$	734.2		$	145.1	$	4,267.9		$	606.9

Number of positions with a gross unrealized loss	2,515					587					3,102
Fair value as a percentage of total fixed maturities securities fair value	68.2		%			14.2		%			82.4		%

Fixed maturity securities with an investment grade rating represented 96.0% of the gross unrealized losses as of December 31, 2023. For the same reasons discussed above, we expect to receive cash flows sufficient to recover the entire amortized cost basis of the securities in the previous table.

The following table presents the distribution of the Company's fixed maturity securities portfolio by estimated expected maturity. Estimated expected maturities differ from contractual maturities, reflecting assumptions regarding borrowers' utilization of the right to call or prepay obligations with or without call or prepayment penalties. For structured securities, estimated expected maturities consider broker-dealer survey prepayment assumptions and are verified for consistency with the interest rate and economic environments.


($ in millions)	December 31, 2023
	Amortized Cost, net		Fair Value		Percent of Total Fair Value
Estimated expected maturity:
Due in 1 year or less	$	298.6	$	294.1	5.6	%
Due after 1 year through 5 years	1,482.4		1,435.5		27.4	%
Due after 5 years through 10 years	1,435.1		1,371.5		26.2	%
Due after 10 years through 20 years	1,426.3		1,282.6		24.5	%
Due after 20 years	1,010.5		851.6		16.3	%
Total	$	5,652.9	$	5,235.3	100.0	%


($ in millions)	Year Ended December 31,
	2023		2022		2021
Fixed maturity securities
Proceeds received	$	377.6	$	752.0	$	578.2
Gross gains realized	2.2		5.5		10.5
Gross losses realized	(14.0)		(23.7)		(7.7)

Equity securities
Proceeds received	$	18.7	$	10.8	$	4.7
Gross gains realized	—		1.7		1.5
Gross losses realized	(11.8)		(1.0)		(0.1)


($ in millions)	Year Ended December 31,
	2023		2022		2021
Net unrealized investment gains (losses) on fixed maturity securities, net of tax
Beginning of period	$	(449.6)	$	347.1	$	366.3
Effect of adopting ASU 2018-12	—		—		71.1
Change in net unrealized investment gains (losses) on fixed maturity securities	105.3		(819.7)		(96.4)
Reclassification of net investment (gains) losses on fixed maturity securities to net income	16.0		23.0		6.1
End of period	$	(328.3)	$	(449.6)	$	347.1

Investments in limited partnership interests are accounted for using the equity method of accounting (EMA) and include interests in commercial mortgage loan funds, real estate equity funds, private equity funds, infrastructure equity funds, infrastructure debt funds and other funds. Principal factors influencing carrying amount appreciation or depreciation include operating performance, comparable public company earnings multiples, capitalization rates and the economic environment. The carrying amounts of EMA limited partnership interests were as follows:

The Company's derivatives are subject to enforceable master netting arrangements. Collateral support agreements associated with each master netting arrangement provides that the Company will receive or pledge financial collateral in the event minimum thresholds have been reached. The Company’s reverse repurchase agreements are also subject to enforceable master netting arrangements but there was no offsetting in their presentation in the Company’s Consolidated Balance Sheets. The following table presents instruments that were subject to a master netting arrangement for the Company.


($ in millions)			Gross Amounts Offset in the Consolidated Balance Sheets		Net Amounts of Assets/ Liabilities Presented in the Consolidated Balance Sheets		Gross Amounts Not Offset in the Consolidated Balance Sheets
	Gross Amounts						Financial Instruments		Cash Collateral Received		Net Amount
December 31, 2023
Asset derivatives
Free-standing derivatives	$	19.0	$	—	$	19.0	$	—	$	18.5	$	0.5

December 31, 2022
Asset derivatives
Free-standing derivatives	$	6.8	$	—	$	6.8	$	—	$	5.9	$	0.9

At December 31, 2023 and 2022, fixed maturity securities with a fair value of $29.2 million and $28.6 million, respectively, were on deposit with governmental agencies as required by law in various states for which the insurance subsidiaries of the Company conduct business. In addition, as of December 31, 2023 and 2022, fixed maturity securities with a fair value of $987.2 million and $860.4 million, respectively, were on deposit with FHLB as collateral for amounts subject to funding agreements, advances and borrowings which were equal to $904.5 million and $792.5 million at the respective dates. The deposited securities are reported as Fixed maturity securities in the Company's Consolidated Balance Sheets.