
	Amortized cost		Gross unrealized gains		Gross unrealized losses		Allowance for credit losses		Estimated fair value
Investment grade (a):
Corporate securities	$	13,107.1	$	55.5	$	(1,632.9)	$	(22.5)	$	11,507.2
Certificates of deposit	470.0		18.3		—		—		$	488.3
United States Treasury securities and obligations of United States government corporations and agencies	214.8		—		(28.6)		—		186.2
States and political subdivisions	3,238.3		12.1		(434.6)		(0.5)		2,815.3
Foreign governments	107.3		0.1		(15.3)		(0.9)		91.2
Asset-backed securities	1,475.1		7.5		(56.6)		(0.1)		1,425.9
Agency residential mortgage-backed securities	819.8		5.3		(5.5)		—		819.6
Non-agency residential mortgage-backed securities	1,253.4		11.5		(121.6)		—		1,143.3
Collateralized loan obligations	1,015.2		5.6		(4.0)		—		1,016.8
Commercial mortgage-backed securities	2,275.3		3.7		(157.8)		—		2,121.2
Total investment grade fixed maturities, available for sale	23,976.3		119.6		(2,456.9)		(24.0)		21,615.0
Below-investment grade (a) (b):
Corporate securities	678.2		4.9		(30.4)		(8.6)		644.1
States and political subdivisions	23.6		0.1		(1.8)		(2.9)		19.0

Asset-backed securities	99.5		0.8		(9.9)		—		90.4

Non-agency residential mortgage-backed securities	382.9		22.0		(9.2)		—		395.7

Commercial mortgage-backed securities	103.8		—		(25.9)		(1.6)		76.3
Total below-investment grade fixed maturities, available for sale	1,288.0		27.8		(77.2)		(13.1)		1,225.5
Total fixed maturities, available for sale	$	25,264.3	$	147.4	$	(2,534.1)	$	(37.1)	$	22,840.5

(a)Investment ratings are assigned the second lowest rating by Nationally Recognized Statistical Rating Organizations ("NRSROs") (Moody's Investor Services, Inc. ("Moody's"), S&P Global Ratings ("S&P") or Fitch Ratings ("Fitch")), or if not rated by such firms, the rating assigned by the National Association of Insurance Commissioners (the "NAIC"). NAIC designations of "1" or "2" include fixed maturities generally rated investment grade (rated "Baa3" or higher by Moody's or rated "BBB-" or higher by S&P and Fitch). NAIC designations of "3" through "6" are referred to as below-investment grade (which generally are rated "Ba1" or lower by Moody's or rated "BB+" or lower by S&P and Fitch). References to investment grade or below-investment grade throughout our consolidated financial statements are determined as described above.

(b)Certain structured securities rated below-investment grade by NRSROs may be assigned a NAIC 1 or NAIC 2 designation based on the cost basis of the security relative to estimated recoverable amounts as determined by the NAIC. Refer to the table below for a summary of our fixed maturity securities, available for sale, by NAIC designations.

The NAIC evaluates the fixed maturity investments of insurers for regulatory and capital assessment purposes and assigns securities to one of six credit quality categories called NAIC designations, which are used by insurers when preparing their annual statements based on U.S. statutory accounting principles. The NAIC designations are generally similar to the credit quality designations of the NRSROs for marketable fixed maturity securities, except for certain structured securities. However, certain structured securities rated below investment grade by the NRSROs can be assigned NAIC 1 or NAIC 2 designations depending on the cost basis of the holding relative to estimated recoverable amounts as determined by the NAIC. The following summarizes the NAIC designations and NRSRO equivalent ratings:


NAIC designation	Amortized cost		Estimated fair value		Percentage of total estimated fair value
1	$	16,091.7	$	14,522.4	63.6	%
2	8,261.4		7,480.6		32.8
Total NAIC 1 and 2 (investment grade)	24,353.1		22,003.0		96.4
3	635.2		598.6		2.6
4	236.2		211.2		0.9
5	18.6		13.9		0.1
6	21.2		13.8		—
Total NAIC 3,4,5 and 6 (below-investment grade)	911.2		837.5		3.6
	$	25,264.3	$	22,840.5	100.0	%


	Amortized cost		Gross unrealized gains		Gross unrealized losses		Allowance for credit losses		Estimated fair value
Investment grade:
Corporate securities	$	12,590.8	$	73.0	$	(1,347.8)	$	(26.6)	$	11,289.4
United States Treasury securities and obligations of United States government corporations and agencies	207.6		0.1		(13.3)		—		194.4
States and political subdivisions	2,887.2		31.3		(360.2)		(0.6)		2,557.7
Foreign governments	92.7		1.2		(10.4)		(0.4)		83.1
Asset-backed securities	1,364.5		3.9		(92.4)		(0.1)		1,275.9
Agency residential mortgage-backed securities	639.0		9.5		(0.5)		—		648.0
Non-agency residential mortgage-backed securities	1,170.8		7.0		(136.3)		—		1,041.5
Collateralized loan obligations	1,042.5		3.3		(13.0)		—		1,032.8
Commercial mortgage-backed securities	2,386.9		0.7		(240.9)		—		2,146.7
Total investment grade fixed maturities, available for sale	22,382.0		130.0		(2,214.8)		(27.7)		20,269.5
Below-investment grade:
Corporate securities	596.1		1.7		(34.6)		(15.1)		548.1
States and political subdivisions	9.6		—		(0.5)		(0.1)		9.0

Asset-backed securities	111.7		0.2		(15.4)		—		96.5

Non-agency residential mortgage-backed securities	499.3		28.8		(16.4)		—		511.7

Commercial mortgage-backed securities	100.5		—		(29.1)		—		71.4
Total below-investment grade fixed maturities, available for sale	1,317.2		30.7		(96.0)		(15.2)		1,236.7
Total fixed maturities, available for sale	$	23,699.2	$	160.7	$	(2,310.8)	$	(42.9)	$	21,506.2

At December 31, 2024, the amortized cost of the Company's below-investment grade fixed maturity securities, available for sale, was $1,288.0 million, or 5.1 percent of the Company's fixed maturity portfolio. The estimated fair value of the below-investment grade portfolio was $1,225.5 million, or 95 percent of the amortized cost. Based on the credit quality ratings assigned by the NAIC: (i) the amortized cost of our below-investment grade fixed maturities was $911.2 million, or 3.6 percent of our fixed maturity portfolio; and (ii) the estimated fair value of such below-investment grade fixed maturities was $837.5 million or 92 percent, of the amortized cost.

Below-investment grade corporate debt securities typically have different characteristics than investment grade corporate debt securities. Based on historical performance, probability of default by the borrower is significantly greater for below-investment grade corporate debt securities and in many cases severity of loss is relatively greater as such securities are generally unsecured and often subordinated to other indebtedness of the issuer. Also, issuers of below-investment grade corporate debt securities frequently have higher levels of debt relative to investment-grade issuers, hence, all other things being equal, are generally more sensitive to adverse economic conditions. The Company attempts to reduce the overall risk related to its investment in below-investment grade securities, as in all investments, through careful credit analysis, strict investment policy guidelines, and diversification by issuer and/or guarantor and by industry.

The following table sets forth the amortized cost and estimated fair value of fixed maturities, available for sale, at December 31, 2024, by contractual maturity. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalties. Structured securities (such as asset-backed securities, agency residential mortgage-backed securities, non-agency residential mortgage-backed securities, collateralized loan obligations and commercial mortgage-backed securities, collectively referred to as "structured securities") frequently include provisions for periodic principal payments and permit periodic unscheduled payments.


	Amortized cost		Estimated fair value
	(Dollars in millions)
Due in one year or less	$	687.7	$	705.3
Due after one year through five years	2,378.9		2,322.4
Due after five years through ten years	2,056.3		2,004.4
Due after ten years	12,716.4		10,719.1
Subtotal	17,839.3		15,751.2
Structured securities	7,425.0		7,089.3
Total fixed maturities, available for sale	$	25,264.3	$	22,840.5


	2024		2023		2022
General account assets:
Fixed maturities	$	1,222.1	$	1,142.9	$	1,084.1
Equity securities	35.0		1.7		5.9
Mortgage loans	126.5		97.4		63.0
Policy loans	9.0		8.6		8.4
Other invested assets	26.8		8.2		38.0
Cash and cash equivalents	39.0		20.9		5.9
Policyholder and other special-purpose portfolios:
Trading securities	5.0		6.5		7.7
Options related to fixed indexed products:
Option income (loss)	243.6		(48.3)		(6.3)
Change in value of options	12.2		177.3		(200.3)
Other special-purpose portfolios	68.7		114.0		35.8
Gross investment income	1,787.9		1,529.2		1,042.2
Less investment expenses	39.1		29.5		26.3
Net investment income	$	1,748.8	$	1,499.7	$	1,015.9


	2024		2023		2022
Realized investment gains (losses):
Gross realized gains on sales of fixed maturities, available for sale	$	11.5	$	13.4	$	99.8
Gross realized losses on sales of fixed maturities, available for sale	(54.9)		(58.9)		(104.0)
Equity securities, net	—		(0.6)		(8.3)
Other, net	(32.2)		(23.2)		(5.4)
Total realized investment gains (losses)	(75.6)		(69.3)		(17.9)
Change in allowance for credit losses and write-downs (a)	(2.6)		8.1		(52.6)
Change in fair value of equity securities (b)	(0.4)		0.4		(2.9)


Gain on dissolution of variable interest entities	3.9		—		—
Other changes in fair value (c)	24.8		(8.2)		(62.0)
Other investment gains (losses)	25.7		0.3		(117.5)
Total investment gains (losses)	$	(49.9)	$	(69.0)	$	(135.4)

During 2024, we recognized net investment losses of $49.9 million, which were comprised of: (i) $75.6 million of net losses from the sales of investments; (ii) $0.4 million of losses related to equity securities, including the change in fair value; (iii) the net increase in fair value of certain other invested assets and fixed maturity investments with embedded derivatives of $24.4 million; (iv) the increase in fair value of embedded derivatives related to a modified coinsurance agreement of $0.4 million; (v) $3.9 million of gains related to the liquidation of VIEs; and (vi) investment write-downs partially offset by a net decrease in the allowance for credit losses of $2.6 million.

During 2023, we recognized net investment losses of $69.0 million, which were comprised of: (i) $68.7 million of net losses from the sales of investments; (ii) $0.2 million of losses related to equity securities, including the change in fair value; (iii) the net decrease in fair value of certain other invested assets and fixed maturity investments with embedded derivatives of $8.5 million; (iv) the increase in fair value of embedded derivatives related to a modified coinsurance agreement of $0.3 million; and (v) a decrease in the allowance for credit losses of $8.1 million.

During 2022, we recognized net investment losses of $135.4 million, which were comprised of: (i) $9.6 million of net losses from the sales of investments; (ii) $11.2 million of losses related to equity securities, including the change in fair value; (iii) the decrease in fair value of certain fixed maturity investments with embedded derivatives of $45.9 million; (iv) the decrease in fair value of embedded derivatives related to a modified coinsurance agreement of $16.1 million; and (v) an increase in the allowance for credit losses of $52.6 million.

During 2024, the $54.9 million of realized losses on sales of $1,432.0 million of fixed maturity securities, available for sale, included: (i) $35.7 million related to various corporate securities; (ii) $12.5 million related to commercial mortgage-backed securities; and (iii) $6.7 million related to various other investments. Securities are generally sold at a loss following unforeseen issuer-specific events or conditions or shifts in perceived relative values. These reasons include but are not limited to: (i) changes in the investment environment; (ii) expectation that the market value could deteriorate; (iii) our desire to reduce our exposure to an asset class, an issuer or an industry; (iv) prospective or actual changes in credit quality; or (v) changes in expected portfolio cash flows.

During 2023, the $58.9 million of realized losses on sales of $712.2 million of fixed maturity securities, available for sale included: (i) $48.8 million related to various corporate securities; (ii) $6.7 million related to commercial mortgage-backed securities; and (iii) $3.4 million related to various other investments.

During 2022, the $104.0 million of realized losses on sales of $1,651.5 million of fixed maturity securities, available for sale included: (i) $70.9 million related to various corporate securities; (ii) $16.5 million related to non-agency residential mortgage-backed securities; (iii) $7.5 million related to states and political subdivisions; and (iv) $9.1 million related to various other investments.

Our fixed maturity investments are generally purchased in the context of various long-term strategies, including funding insurance liabilities, so we do not generally seek to generate short-term realized gains through the purchase and sale of such securities. In certain circumstances, including those in which securities are selling at prices which exceed our view of their underlying economic value, or when it is possible to reinvest the proceeds to better meet our long-term asset-liability objectives, we may sell certain securities.

The following table sets forth the amortized cost and estimated fair value of those fixed maturities, available for sale, with unrealized losses at December 31, 2024, by contractual maturity. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without penalties. Structured securities frequently include provisions for periodic principal payments and permit periodic unscheduled payments.


	Amortized cost		Estimated fair value
	(Dollars in millions)
Due in one year or less	$	133.0	$	131.8
Due after one year through five years	1,618.5		1,551.5
Due after five years through ten years	1,244.2		1,166.8
Due after ten years	11,659.1		9,625.7
Subtotal	14,654.8		12,475.8
Structured securities	4,693.4		4,301.2
Total	$	19,348.2	$	16,777.0

The following table summarizes the gross unrealized losses and fair values of our investments with unrealized losses for which an allowance for credit losses has not been recorded, aggregated by investment category and length of time that such securities have been in a continuous unrealized loss position, at December 31, 2024 (dollars in millions):


	Less than 12 months				12 months or greater				Total
Description of securities	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Corporate securities	$	1,200.7	$	(35.5)	$	4,035.6	$	(740.7)	$	5,236.3	$	(776.2)
United States Treasury securities and obligations of United States government corporations and agencies	44.7		(3.8)		141.5		(24.8)		186.2		(28.6)
States and political subdivisions	831.9		(20.5)		896.1		(212.1)		1,728.0		(232.6)
Foreign governments	17.4		(1.0)		10.0		(1.1)		27.4		(2.1)
Asset-backed securities	124.8		(1.3)		807.9		(64.3)		932.7		(65.6)
Agency residential mortgage-backed securities	297.1		(5.3)		3.1		(0.2)		300.2		(5.5)
Non-agency residential mortgage-backed securities	128.0		(1.4)		884.6		(129.4)		1,012.6		(130.8)
Collateralized loan obligations	162.9		(0.7)		66.8		(3.3)		229.7		(4.0)
Commercial mortgage-backed securities	174.5		(1.2)		1,642.7		(182.5)		1,817.2		(183.7)
Total fixed maturities, available for sale	$	2,982.0	$	(70.7)	$	8,488.3	$	(1,358.4)	$	11,470.3	$	(1,429.1)


	Less than 12 months				12 months or greater				Total
Description of securities	Fair value		Unrealized losses		Fair value		Unrealized losses		Fair value		Unrealized losses
Corporate securities	$	332.0	$	(5.3)	$	5,199.0	$	(640.6)	$	5,531.0	$	(645.9)
United States Treasury securities and obligations of United States government corporations and agencies	126.7		(10.2)		34.5		(3.1)		161.2		(13.3)
States and political subdivisions	236.9		(3.8)		990.0		(181.2)		1,226.9		(185.0)
Foreign governments	6.2		—		21.1		(2.3)		27.3		(2.3)
Asset-backed securities	46.9		(0.8)		1,066.8		(106.0)		1,113.7		(106.8)
Agency residential mortgage-backed securities	73.4		(0.4)		7.1		(0.1)		80.5		(0.5)
Non-agency residential mortgage-backed securities	69.0		(1.3)		1,062.9		(151.4)		1,131.9		(152.7)
Collateralized loan obligations	75.0		(0.3)		590.9		(12.7)		665.9		(13.0)
Commercial mortgage-backed securities	203.8		(2.4)		1,914.1		(267.6)		2,117.9		(270.0)
Total fixed maturities, available for sale	$	1,169.9	$	(24.5)	$	10,886.4	$	(1,365.0)	$	12,056.3	$	(1,389.5)

Based on management's current assessment of investments with unrealized losses at December 31, 2024, the Company believes the issuers of the securities will continue to meet their obligations. While we do not have the intent to sell securities with unrealized losses and it is not more likely than not that we will be required to sell securities with unrealized losses prior to their anticipated recovery, our intent on an individual security may change, based upon market or other unforeseen developments. In such instances, if a loss is recognized from a sale subsequent to a balance sheet date due to these unexpected developments, the loss is recognized in the period in which we had the intent to sell the security before its anticipated recovery.


	Corporate securities		States and political subdivisions		Foreign governments		Asset-backed securities		Commercial mortgage-backed securities		Total
Allowance at December 31, 2021	$	7.4	$	—	$	0.2	$	—	$	—	$	7.6
Additions for securities for which credit losses were not previously recorded	48.9		0.7		0.5		0.3		—		50.4
Additions (reductions) for securities where an allowance was previously recorded	10.3		0.3		(0.3)		—		—		10.3
Reduction for securities disposed during the period	(12.2)		(0.1)		—		—		—		(12.3)
Allowance at December 31, 2022	54.4		0.9		0.4		0.3		—		56.0
Additions for securities for which credit losses were not previously recorded	7.3		0.3		0.1		—		—		7.7
Additions (reductions) for securities where an allowance was previously recorded	(7.3)		(0.4)		—		(0.2)		—		(7.9)
Reduction for securities disposed during the period	(12.7)		(0.1)		(0.1)		—		—		(12.9)
Allowance at December 31, 2023	41.7		0.7		0.4		0.1		—		42.9
Additions for securities for which credit losses were not previously recorded	8.9		—		0.3		—		1.6		10.8
Additions (reductions) for securities where an allowance was previously recorded	(9.2)		2.7		0.3		—		—		(6.2)
Reduction for securities disposed during the period	(10.3)		(0.1)		—		—		—		(10.4)
Allowance at December 31, 2024	$	31.1	$	3.3	$	1.0	$	0.1	$	1.6	$	37.1

At December 31, 2024, fixed maturity investments included structured securities with an estimated fair value of $7.1 billion (or 31.0 percent of all fixed maturity securities). The yield characteristics of structured securities generally differ in some respects from those of traditional corporate fixed income securities or government securities. For example, interest and principal payments on structured securities may occur more frequently, often monthly. In many instances, we are subject to variability in the amount and timing of principal and interest payments. For example, in many cases, partial prepayments may occur at the option of the issuer and prepayment rates are influenced by a number of factors that cannot be predicted with certainty, including: the relative sensitivity of prepayments on the underlying assets backing the security to changes in interest rates and asset values; the availability of alternative financing; a variety of economic, geographic and

other factors; the timing, pace and proceeds of liquidations of defaulted collateral; and various security-specific structural considerations (for example, the repayment priority of a given security in a securitization structure). In addition, the total amount of payments for non-agency structured securities may be affected by changes to cumulative default rates or loss severities of the related collateral.

Historically, the rate of prepayments on structured securities has tended to increase when prevailing interest rates have declined significantly in absolute terms and also relative to the interest rates on the underlying collateral. The yields recognized on structured securities purchased at a discount to par will generally increase (relative to the stated rate) when the underlying collateral prepays faster than expected. The yields recognized on structured securities purchased at a premium will decrease (relative to the stated rate) when the underlying collateral prepays faster than expected. When interest rates decline, the proceeds from prepayments may be reinvested at lower rates than we were earning on the prepaid securities. When interest rates increase, prepayments may decrease below expected levels. When this occurs, the average maturity and duration of structured securities increases, decreasing the yield on structured securities purchased at discounts and increasing the yield on those purchased at a premium because of a decrease in the annual amortization of premium.

For structured securities included in fixed maturities, available for sale, that were purchased at a discount or premium, we recognize investment income using an effective yield based on anticipated future prepayments and the estimated final maturity of the securities. Actual prepayment experience is periodically reviewed and effective yields are recalculated when differences arise between the prepayments originally anticipated and the actual prepayments received and currently anticipated. For credit sensitive mortgage-backed and asset-backed securities, and for securities that can be prepaid or settled in a way that we would not recover substantially all of our investment, the effective yield is recalculated on a prospective basis. Under this method, the amortized cost basis in the security is not immediately adjusted and a new yield is applied prospectively. For all other structured and asset-backed securities, the effective yield is recalculated when changes in assumptions are made, and reflected in our income on a retrospective basis. Under this method, the amortized cost basis of the investment in the securities is adjusted to the amount that would have existed had the new effective yield been applied since the acquisition of the securities. Such adjustments were not significant in 2024.

For purchased credit impaired securities, at acquisition, the difference between the undiscounted expected future cash flows and the recorded investment in the securities represents the initial accretable yield, which is accreted into net investment income over the securities’ remaining lives on a level-yield basis. Subsequently, effective yields recognized on purchased credit impaired securities are recalculated and adjusted prospectively to reflect changes in the contractual benchmark interest rates on variable rate securities and any significant increases in undiscounted expected future cash flows arising due to reasons other than interest rate changes. Significant decreases in expected cash flows arising from credit events would result in impairment if such security's fair value is below amortized cost.


			Estimated fair value
Type	Amortized cost		Amount		Percent of fixed maturities
Asset-backed securities	$	1,574.6	$	1,516.4	6.6	%
Agency residential mortgage-backed securities	819.8		819.6		3.6
Non-agency residential mortgage-backed securities	1,636.3		1,539.1		6.7
Collateralized loan obligations	1,015.2		1,016.8		4.5
Commercial mortgage-backed securities	2,379.1		2,197.4		9.6

Total structured securities	$	7,425.0	$	7,089.3	31.0	%

Residential mortgage-backed securities ("RMBS") include transactions collateralized by agency-guaranteed and non-agency mortgage obligations. Non-agency RMBS investments are primarily categorized by underlying borrower credit quality: Prime, Alt-A, Non-Qualified Mortgage ("Non-QM"), and Subprime. Prime borrowers typically default with the lowest frequency, Alt-A and Non-QM default at higher rates, and Subprime borrowers default with the highest

frequency. In addition to borrower credit categories, RMBS investments include Re-Performing Loan ("RPL") and Credit Risk Transfer ("CRT") transactions. RPL transactions include borrowers with prior difficulty meeting the original mortgage terms and were subsequently modified, resulting in a sustainable payback arrangement. CRT securities are collateralized by Government-Sponsored Enterprise conforming mortgages and Prime borrowers, but without an agency guarantee against default losses.

Commercial mortgage-backed securities ("CMBS") are secured by commercial real estate mortgages, generally income producing properties that are managed for profit. Property types include, but are not limited to, hospitals, hotels, multi-family dwellings including apartments, nursing homes, office buildings, restaurants, retail centers and warehouses. While most CMBS have call protection features whereby underlying borrowers may not prepay their mortgages for stated periods of time without incurring prepayment penalties, recoveries on defaulted collateral may result in involuntary prepayments.

Mortgage loans are carried at amortized unpaid balance, net of allowance for estimated credit losses. Interest income is accrued on the principal amount of the loan based on the loan's contractual interest rate. Payment terms specified for mortgage loans may include a prepayment penalty for unscheduled payoff of the investment. Prepayment penalties are recognized as investment income when received.

The mortgage loan balance was comprised of commercial and residential mortgage loans. At December 31, 2024, we held commercial mortgage loan investments with an amortized cost and fair value of $1,501.4 million and $1,344.2 million, respectively. Approximately 17 percent, 7 percent, 6 percent, 6 percent and 5 percent of the commercial mortgage loan balance were on properties located in California, Maryland, Wisconsin, Utah and Georgia, respectively. No other state comprised greater than five percent of the commercial mortgage loan balance. At December 31, 2024, there were no commercial mortgage loans in process of foreclosure.


															Estimated fair value
Loan-to-value ratio (a)	2024		2023		2022		2021		2020		Prior		Total amortized cost		Mortgage loans		Collateral
Less than 60%	$	153.9	$	170.6	$	130.1	$	134.1	$	37.5	$	443.4	$	1,069.6	$	962.1	$	4,189.1
60% to less than 70%	31.3		92.9		39.1		5.8		—		28.5		197.6		181.2		304.6
70% to less than 80%	—		42.3		77.6		—		—		38.5		158.4		139.2		214.6
80% to less than 90%	—		—		61.2		—		—		—		61.2		51.7		75.9
90% or greater	—		—		—		—		—		14.6		14.6		10.0		15.1
Total	$	185.2	$	305.8	$	308.0	$	139.9	$	37.5	$	525.0	$	1,501.4	$	1,344.2	$	4,799.3

At December 31, 2024, we held residential mortgage loan investments with an amortized cost of $1,018.6 million and a fair value of $1,031.8 million. Our primary credit quality indicator for these investments is whether the loan is current or non-current. We define non-current loans as those that are 90 or more days past due and/or in nonaccrual status. At December 31, 2024, there were 21 residential mortgage loans that were non-current with an amortized cost of $15.6 million (of which, eight loans with an amortized cost of $3.7 million were in foreclosure).

The allowance for estimated credit losses is measured using a loss-rate method on an individual asset basis. Inputs used include asset-specific characteristics, current economic conditions, historical loss information and reasonable and supportable forecasts about future economic conditions. The following table summarizes changes in the allowance for credit losses related to mortgage loans for each of the three years ended December 31, 2024 (dollars in millions):


	Mortgage loans
Allowance for credit losses at December 31, 2021	$	5.6
Current period provision for expected credit losses	2.4
Allowance for credit losses at December 31, 2022	8.0
Current period provision for expected credit losses	7.4
Allowance for credit losses at December 31, 2023	15.4
Current period provision for expected credit losses	(1.8)
Allowance for credit losses at December 31, 2024	$	13.6