The amortized cost and fair value of available-for-sale fixed maturities were as follows:

	June 30, 2021
						Amortized Cost,
			Allowance			Net of Allowance		Gross		Gross
	Amortized		for Credit			for Credit		Unrealized		Unrealized
(in millions)	Cost		Losses			Losses		Gains		Losses		Fair Value
U.S. Treasury and government agencies	$	381.5	$	—		$	381.5	$	12.1	$	6.7	$	386.9
Foreign government		2.2		—			2.2		0.4		—		2.6
Municipal		1,053.9		—			1,053.9		45.3		2.0		1,097.2
Corporate		3,965.5		(0.1	)		3,965.4		256.2		8.2		4,213.4
Residential mortgage-backed		980.0		—			980.0		22.0		4.2		997.8
Commercial mortgage-backed		739.3		—			739.3		41.8		1.5		779.6
Asset-backed		75.7		—			75.7		2.6		—		78.3
Total fixed maturities	$	7,198.1	$	(0.1	)	$	7,198.0	$	380.4	$	22.6	$	7,555.8

	December 31, 2020
						Amortized Cost,
			Allowance			Net of Allowance		Gross		Gross
	Amortized		for Credit			for Credit		Unrealized		Unrealized
(in millions)	Cost		Losses			Losses		Gains		Losses		Fair Value
U.S. Treasury and government agencies	$	376.4	$	—		$	376.4	$	17.6	$	2.0	$	392.0
Foreign government		2.2		—			2.2		0.5		—		2.7
Municipal		1,042.1		—			1,042.1		61.7		0.1		1,103.7
Corporate		3,770.0		(0.1	)		3,769.9		341.8		0.4		4,111.3
Residential mortgage-backed		978.2		—			978.2		33.1		0.6		1,010.7
Commercial mortgage-backed		705.4		—			705.4		54.8		0.2		760.0
Asset-backed		71.4		—			71.4		2.6		—		74.0
Total fixed maturities	$	6,945.7	$	(0.1	)	$	6,945.6	$	512.1	$	3.3	$	7,454.4

The Company deposits funds with various state and governmental authorities. For a discussion of the Company’s deposits with state and governmental authorities, see also Note 3 – “Investments” in the Notes to Consolidated Financial Statements in the Company’s 2020 Annual Report on Form 10-K.

The amortized cost and fair value by maturity periods for fixed maturities are shown in the following table. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties, or the Company may have the right to put or sell the obligations back to the issuers.

	June 30, 2021
	Amortized Cost, Net
	of Allowance for		Fair
(in millions)	Credit Losses		Value
Due in one year or less	$	268.9	$	272.7
Due after one year through five years		1,907.3		2,040.1
Due after five years through ten years		2,491.1		2,639.1
Due after ten years		735.7		748.2
		5,403.0		5,700.1
Mortgage-backed and asset-backed securities		1,795.0		1,855.7
Total fixed maturities	$	7,198.0	$	7,555.8

The following tables provide information about the Company’s available-for-sale fixed maturity securities that were in an unrealized loss position at June 30, 2021 and December 31, 2020, including the length of time the securities have been in an unrealized loss position:

	June 30, 2021
	12 months or less				Greater than 12 months				Total
	Gross				Gross				Gross
	Unrealized		Fair		Unrealized		Fair		Unrealized		Fair
(in millions)	Losses		Value		Losses		Value		Losses		Value
Investment grade:
U.S. Treasury and government agencies	$	6.7	$	185.4	$	—	$	—	$	6.7	$	185.4
Municipal		2.0		176.1		—		0.5		2.0		176.6
Corporate		7.2		298.4		—		—		7.2		298.4
Residential mortgage-backed		4.2		304.5		—		—		4.2		304.5
Commercial mortgage-backed		1.5		72.3		—		—		1.5		72.3
Total investment grade		21.6		1,036.7		—		0.5		21.6		1,037.2
Below investment grade:
Corporate		1.0		42.0		—		—		1.0		42.0
Total fixed maturities	$	22.6	$	1,078.7	$	—	$	0.5	$	22.6	$	1,079.2

	December 31, 2020
	12 months or less				Greater than 12 months				Total
	Gross				Gross				Gross
	Unrealized		Fair		Unrealized		Fair		Unrealized		Fair
(in millions)	Losses		Value		Losses		Value		Losses		Value
Investment grade:
U.S. Treasury and government agencies	$	2.0	$	140.7	$	—	$	—	$	2.0	$	140.7
Municipal		0.1		19.3		—		0.7		0.1		20.0
Corporate		0.4		53.4		—		—		0.4		53.4
Residential mortgage-backed		0.6		94.4		—		—		0.6		94.4
Commercial mortgage-backed		0.2		33.2		—		—		0.2		33.2
Total investment grade		3.3		341.0		—		0.7		3.3		341.7
Below investment grade:
Corporate		—		4.6		—		—		—		4.6
Total fixed maturities	$	3.3	$	345.6	$	—	$	0.7	$	3.3	$	346.3

The Company views gross unrealized losses on fixed maturities as non-credit related and through its assessment of unrealized losses has determined that these securities will recover, allowing the Company to realize the anticipated long-term economic value. The Company currently does not intend to sell, nor does it expect to be required to sell these securities before recovery of their amortized cost. The Company employs a systematic methodology to evaluate declines in fair value below amortized cost for fixed maturity securities. In determining impairments, the Company evaluates several factors and circumstances, including the issuer’s overall financial condition; the issuer’s credit and financial strength ratings; the issuer’s financial performance, including earnings trends and asset quality; any specific events which may influence the operations of the issuer; the general outlook for market conditions in the industry or geographic region in which the issuer operates; and the degree to which the fair value of an issuer’s securities is below the Company’s amortized cost. The Company also considers any factors that might raise doubt about the issuer’s ability to make contractual payments as they come due and whether the Company expects to recover the entire amortized cost basis of the security.

The proceeds from sales of available-for-sale fixed maturities and gross realized gains and gross realized losses on those sales were as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
(in millions)
Proceeds from sales	$	34.7	$	91.5	$	252.1	$	157.5
Gross gains		1.0		2.3		3.9		5.0
Gross losses		0.2		2.3		7.4		2.7

For the three and six months ended June 30, 2021, the Company recognized impairments of $0.2 million on fixed maturities. For the three months ended June 30, 2020, the Company recognized a $1.4 million net recovery in impairment losses on fixed maturities, primarily resulting from increased market values during the quarter on credit losses recognized in the first quarter of 2020. For the six months ended June 30, 2020, the Company recognized $27.1 million of impairment losses, consisting primarily of $20.8 million on fixed maturities and $4.8 million on mortgage loans. Impairments on fixed maturities included $16.2 million categorized as intend-to-sell and $4.6 million of credit-related losses.

At June 30, 2021 and December 31, 2020, the allowance for credit losses on mortgage loans was $7.9 million and the allowance for credit losses on available-for-sale debt securities was $0.1 million.

The methodology and significant inputs used to measure the amount of credit losses were as follows:

Fixed maturities, Corporate bonds – the Company utilized a financial model that derives expected cash flows based on probability-of-default factors by credit rating and asset duration, and loss-given-default factors based on security type. These factors are based on historical data provided by an independent third-party rating agency. In addition, other qualitative market data relevant to the realizability of contractual cash flows may be considered, including current conditions and reasonable and supportable forecasts.

Mortgage loans – the Company estimated losses by applying expected loss rates, which are based on historical data. Embedded in expected loss rates are mortgage risk ratings and risk factors associated with property type such as office, retail, lodging, multi-family and industrial. Risk ratings, based on property characteristics and metrics including the geographic market, are predominantly driven by estimates of loan-to-value and debt service coverage ratios. Ratings may be adjusted to reflect current conditions and to incorporate reasonable and supportable forecasts, such as volatility of cash flows and valuation.

Equity securities are carried at fair value and all increases or decreases in fair value are reported in net realized and unrealized investment gains (losses) on the Consolidated Statements of Income. The following table provides pre-tax net realized and unrealized gains (losses) on equity securities:

	Three Months Ended June 30,						Six Months Ended June 30,
(in millions)		2021			2020			2021		2020
Net gains (losses) recognized during the period	$	26.5		$	61.5		$	65.6	$	(74.7	)
Less: net (losses) gains recognized on equity securities sold during the period		(0.1	)		(15.8	)		0.5		(16.4	)
Net unrealized gains (losses) recognized during the period on equity securities still held	$	26.6		$	77.3		$	65.1	$	(58.3	)