The amortized cost, gross unrealized gains and losses, and fair value of investments in fixed income securities classified as available-for-sale at June 30, 2020 and December 31, 2019 are shown in tables 7.1a and 7.1b below.



Details of fixed income securities by category as of June 30, 2020
Table	7.1a
(In thousands)		Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses) ⁽¹⁾			Fair Value
U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	346,881	$	1,777	$	(41	)	$	348,617
Obligations of U.S. states and political subdivisions		1,666,017		124,251		(1,291		)	1,788,977
Corporate debt securities		2,514,526		137,465		(5,160		)	2,646,831
Asset backed securities (“ABS”)		198,238		4,034		(2,716		)	199,556
Residential mortgage backed securities (“RMBS”)		293,790		6,055		(353		)	299,492
Commercial mortgage backed securities (“CMBS”)		264,857		10,453		(1,411		)	273,899
Collateralized loan obligations (“CLOs”)		313,245		—		(8,355		)	304,890
Total fixed income securities		$	5,597,554	$	284,035	$	(19,327	)	$	5,862,262



Details of fixed income securities by category as of December 31, 2019
Table	7.1b
(In thousands)		Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses) ⁽²⁾			Fair Value
U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	195,176	$	1,237	$	(210	)	$	196,203
Obligations of U.S. states and political subdivisions		1,555,394		99,328		(857		)	1,653,865
Corporate debt securities		2,711,910		76,220		(3,008		)	2,785,122
ABS		227,376		2,466		(178		)	229,664
RMBS		271,384		429		(3,227		)	268,586
CMBS		274,234		5,531		(779		)	278,986
CLOs		327,076		33		(1,643		)	325,466
Total fixed income securities		$	5,562,550	$	185,244	$	(9,902	)	$	5,737,892

We had $14.2 million and $13.9 million of investments at fair value on deposit with various states as of June 30, 2020 and December 31, 2019, respectively, due to regulatory requirements of those state insurance departments.

The amortized cost and fair values of fixed income securities at June 30, 2020, by contractual maturity, are shown in table 7.2 below. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. Because most ABS, RMBS, CMBS, and CLOs provide for periodic payments throughout their lives, they are listed in separate categories.



Fixed income securities maturity schedule
Table	7.2
		June 30, 2020
(In thousands)		Amortized cost		Fair Value
Due in one year or less		$	465,716	$	469,024
Due after one year through five years		1,854,619		1,935,032
Due after five years through ten years		1,009,452		1,096,842
Due after ten years		1,197,637		1,283,527
		4,527,424		4,784,425

ABS		198,238		199,556
RMBS		293,790		299,492
CMBS		264,857		273,899
CLOs		313,245		304,890
Total as of June 30, 2020		$	5,597,554	$	5,862,262

Proceeds from sales of fixed income securities classified as available-for-sale were $448.5 million and $183.6 million during the six months ended June 30, 2020 and 2019, respectively. Gross gains of $7.3 million and $12.4 million and gross losses of $3.7 million and $5.0 million were realized during the three and six months ended June 30, 2020, respectively. We did not record realized losses for the three months ended June 30,2020 and recorded realized losses of $0.3 million for the six months ended June 30, 2020 related to our intent to sell certain securities. Gross gains of $1.2 million and $2.0 million and gross losses of $1.1 million and $2.3 million were realized on those sales during the three and six months ended June 30, 2019, respectively, and we recorded OTTI losses of $0.1 million for the six months ended June 30, 2019. Realized investment gains and losses are reported in income based on specific identification of securities sold.

For the three and six months ended June 30, 2020, we recognized $1.2 million and $0.3 million of net gains on equity securities still held as of June 30, 2020. For the three and six months ended June 30, 2019, we recognized $0.1 million and $0.2 million of net gains on equity securities still held as of June 30, 2019.

Other invested assets include an investment in Federal Home Loan Bank ("FHLB") stock that is carried at cost, which due to its nature approximates fair value. Ownership of FHLB stock provides access to a secured lending facility, and our current FHLB Advance amount is secured by eligible collateral whose fair value is maintained at a minimum of 102% of the outstanding principal balance of the FHLB Advance. As of June 30, 2020, that collateral consisted of fixed income securities included in our total investment portfolio, and cash and cash equivalents, with a total fair value of $165.8 million.

Tables 7.4a and 7.4b below summarize, for all available-for-sale investments in an unrealized loss position at June 30, 2020 and December 31, 2019, the aggregate fair value and gross unrealized loss by the length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in tables 7.4a and 7.4b are estimated using the process described in Note 8 - “Fair Value Measurements” to these consolidated financial statements and in Note 3 - “Significant Accounting Policies” of the notes to the consolidated financial statements in our 2019 Annual Report on Form 10-K.



Unrealized loss aging for securities by type and length of time as of June 30, 2020
Table	7.4a
		Less Than 12 Months					12 Months or Greater					Total
(In thousands)		Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	207,786	$	(41	)	$	—	$	—		$	207,786	$	(41	)
Obligations of U.S. states and political subdivisions		37,445		(1,291		)	—		—			37,445		(1,291		)
Corporate debt securities		175,570		(5,160		)	—		—			175,570		(5,160		)
ABS		17,415		(2,716		)	—		—			17,415		(2,716		)
RMBS		51,169		(284		)	4,913		(69		)	56,082		(353		)
CMBS		28,609		(1,397		)	3,225		(14		)	31,834		(1,411		)
CLOs		162,838		(3,831		)	142,051		(4,524		)	304,889		(8,355		)
Total		$	680,832	$	(14,720	)	$	150,189	$	(4,607	)	$	831,021	$	(19,327	)



Unrealized loss aging for securities by type and length of time as of December 31, 2019
Table	7.4b
		Less Than 12 Months					12 Months or Greater					Total
(In thousands)		Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government corporations and agencies		$	57,301	$	(200	)	$	5,806	$	(10	)	$	63,107	$	(210	)
Obligations of U.S. states and political subdivisions		74,859		(847		)	6,957		(10		)	81,816		(857		)
Corporate debt securities		221,357		(2,847		)	43,505		(161		)	264,862		(3,008		)
ABS		21,542		(118		)	3,851		(60		)	25,393		(178		)
RMBS		105,443		(461		)	110,452		(2,766		)	215,895		(3,227		)
CMBS		62,388		(728		)	11,852		(51		)	74,240		(779		)
CLOs		81,444		(225		)	196,988		(1,418		)	278,432		(1,643		)
Total		$	624,334	$	(5,426	)	$	379,411	$	(4,476	)	$	1,003,745	$	(9,902	)

Based on current facts and circumstances, we believe the unrealized losses as of June 30, 2020 presented in table 7.4a above are not indicative of the ultimate collectability of the current amortized cost of the securities and a credit loss allowance is not required. We believe the gross unrealized losses are primarily attributable to widening credit spreads over risk free rates, as a result of economic and market uncertainties arising from the COVID-19 pandemic, which includes demand shocks in multiple sectors that originated in the first half of 2020.