Summary of Investments

The following tables summarize fixed maturity investments classified as available-for-sale and the non-credit-related component of other-than-temporary impairments (“OTTI”) in accumulated other comprehensive income (loss) (“AOCI”):



	September 30, 2018
	Amortized		Gross unrealized		Gross unrealized		Estimated fair value		OTTI (gain) loss
Fixed maturities:	cost		gains		losses		and carrying value		included in AOCI ⁽¹⁾
U.S. government direct obligations and U.S. agencies	$	1,446,233	$	22,552	$	42,690	$	1,426,095	$	—
Obligations of U.S. states and their subdivisions	1,828,711		137,944		7,530		1,959,125		—
Corporate debt securities ⁽²⁾	15,593,111		222,689		475,892		15,339,908		(684		)
Asset-backed securities	1,530,147		63,096		24,504		1,568,739		(37,382		)
Residential mortgage-backed securities	74,403		1,813		969		75,247		(50		)
Commercial mortgage-backed securities	1,287,600		3,725		45,827		1,245,498		—
Collateralized debt obligations	936,268		870		1,448		935,690		—
Total fixed maturities	$	22,696,473	$	452,689	$	598,860	$	22,550,302	$	(38,116	)

⁽¹⁾ Indicates the amount of any OTTI (gain) loss included in AOCI that is included in gross unrealized gains and losses. OTTI (gain) loss included in AOCI, as presented above, includes both the initial recognition of non-credit losses and the effects of subsequent increases and decreases in estimated fair value for those fixed maturity securities with previous non-credit impairment. The non-credit loss component of OTTI (gain) loss was in an unrealized gain position due to increases in estimated fair value subsequent to initial recognition of non-credit losses on such securities.

⁽²⁾ Includes perpetual debt investments with amortized cost of $89,267 and estimated fair value of $80,673.



	December 31, 2017
	Amortized		Gross unrealized		Gross unrealized		Estimated fair value		OTTI (gain) loss
Fixed maturities:	cost		gains		losses		and carrying value		included in AOCI ⁽¹⁾
U.S. government direct obligations and U.S. agencies	$	1,837,748	$	41,777	$	7,883	$	1,871,642	$	—
Obligations of U.S. states and their subdivisions	1,872,120		220,507		1,655		2,090,972		—
Corporate debt securities ⁽²⁾	15,234,473		581,991		110,377		15,706,087		(1,018		)
Asset-backed securities	1,622,806		105,301		10,131		1,717,976		(56,735		)
Residential mortgage-backed securities	63,187		2,446		649		64,984		(140		)
Commercial mortgage-backed securities	1,352,906		17,692		12,989		1,357,609		—
Collateralized debt obligations	779,722		4,227		80		783,869		—
Total fixed maturities	$	22,762,962	$	973,941	$	143,764	$	23,593,139	$	(57,893	)

⁽²⁾ Includes perpetual debt investments with amortized cost of $89,267 and estimated fair value of $87,348.

See Note 8 for additional discussion regarding fair value measurements.

The amortized cost and estimated fair value of fixed maturity investments classified as available-for-sale, by contractual maturity date, are shown in the table below. Actual maturities will likely differ from these projections because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



	September 30, 2018
	Amortized cost		Estimated fair value
Maturing in one year or less	$	624,398	$	623,752
Maturing after one year through five years	3,470,116		3,451,165
Maturing after five years through ten years	8,251,124		8,071,691
Maturing after ten years	5,419,415		5,501,579
Mortgage-backed and asset-backed securities	4,931,420		4,902,115
Total fixed maturities	$	22,696,473	$	22,550,302

Mortgage-backed (commercial and residential) and asset-backed securities include those issued by the U.S. government and U.S. agencies.

The following table summarizes information regarding the sales of securities classified as available-for-sale:



	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Proceeds from sales	$	433,643	$	339,051	$	1,911,262	$	2,810,599
Gross realized gains from sales	5,887		8,512		30,613		29,433
Gross realized losses from sales	3,650		2,993		19,722		24,330

Mortgage loans on real estate — The recorded investment of the mortgage loan portfolio categorized as performing was $4,365,962 and $4,005,960 as of September 30, 2018 and December 31, 2017, respectively.

The following table summarizes activity in the mortgage provision allowance:



	Nine Months Ended September 30, 2018		Year Ended December 31, 2017
	Commercial mortgages		Commercial mortgages
Beginning balance	$	773	$	2,882
Provision increases	—		157
Charge-off	—		(663		)
Recovery	—		(30		)
Provision decreases	—		(1,573		)
Ending balance	$	773	$	773

Allowance ending balance by basis of impairment method:
Collectively evaluated for impairment	773		773

Recorded investment balance in the mortgage loan portfolio, gross of allowance, by basis of impairment method:	$	4,365,962	$	4,005,960
Individually evaluated for impairment	2,725		2,942
Collectively evaluated for impairment	4,363,237		4,003,018

Limited partnership interests — Limited partnership interests represent the Company’s minority ownership interests in pooled investment funds that primarily make private equity investments across diverse industries and geographical focuses. The Company has determined its interest in each limited partnership to be considered a variable interest entity (“VIE”). Consolidation is not required as the Company is not deemed to be the primary beneficiary of the VIEs. The carrying value and maximum exposure to loss in relation to the activities of the VIEs was $71,895 and $45,540 at September 30, 2018 and December 31, 2017, respectively.

Securities lending — Securities with a cost or amortized cost of $89,641 and estimated fair values of $84,511 were on loan under the program at September 30, 2018. There were no securities on loan at December 31, 2017. The Company received cash of $66,784 and securities with a fair value of $21,026 as collateral at September 30, 2018. The Company bears the risk of any deficiency in the amount of collateral available for return to a borrower due to a loss in an approved investment.

Under the securities lending program the collateral pledged is, by definition, the securities loaned against the cash borrowed. The following table summarizes the cash collateral liability under the securities lending program, by class of securities loaned:



	September 30, 2018		December 31, 2017
Cash collateral liability by class of loaned security
U.S. government direct obligations and U.S. agencies	$	7,700	$	—
Corporate debt securities	59,084		—
Total	$	66,784	$	—

The Company’s securities lending agreements are open agreements meaning the borrower can return and the Company can recall the loaned securities at any time. The assets and liabilities associated with securities lending program are not subject to master netting arrangements and are not offset in the condensed consolidated balance sheets.

Unrealized losses on fixed maturity investments classified as available-for-sale — The following tables summarize unrealized investment losses, including the non-credit-related portion of OTTI losses reported in AOCI, by class of investment:



	September 30, 2018
	Less than twelve months				Twelve months or longer				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
Fixed maturities:	fair value		loss and OTTI		fair value		loss and OTTI		fair value		loss and OTTI
U.S. government direct obligations and U.S. agencies	$	821,260	$	29,409	$	251,365	$	13,281	$	1,072,625	$	42,690
Obligations of U.S. states and their subdivisions	230,553		4,602		37,812		2,928		268,365		7,530
Corporate debt securities	8,692,153		291,447		2,291,736		184,445		10,983,889		475,892
Asset-backed securities	649,403		13,531		299,315		10,973		948,718		24,504
Residential mortgage-backed securities	3,395		70		9,621		899		13,016		969
Commercial mortgage-backed securities	745,307		22,217		366,889		23,610		1,112,196		45,827
Collateralized debt obligations	346,122		1,448		—		—		346,122		1,448
Total fixed maturities	$	11,488,193	$	362,724	$	3,256,738	$	236,136	$	14,744,931	$	598,860
Total number of securities in an unrealized loss position			1,061				385				1,446



	December 31, 2017
	Less than twelve months				Twelve months or longer				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
Fixed maturities:	fair value		loss and OTTI		fair value		loss and OTTI		fair value		loss and OTTI
U.S. government direct obligations and U.S. agencies	$	755,861	$	4,159	$	230,447	$	3,724	$	986,308	$	7,883
Obligations of U.S. states and their subdivisions	24,908		180		37,012		1,475		61,920		1,655
Corporate debt securities	2,229,585		19,568		2,036,323		90,809		4,265,908		110,377
Asset-backed securities	544,778		3,011		245,341		7,120		790,119		10,131
Residential mortgage-backed securities	4,405		23		11,416		626		15,821		649
Commercial mortgage-backed securities	342,820		2,451		295,164		10,538		637,984		12,989
Collateralized debt obligations	7,277		80		—		—		7,277		80
Total fixed maturities	$	3,909,634	$	29,472	$	2,855,703	$	114,292	$	6,765,337	$	143,764
Total number of securities in an unrealized loss position			368				293				661

Fixed maturity investments — Total unrealized losses and OTTI increased by $455,096, or 317%, from December 31, 2017 to September 30, 2018. The majority, or $333,252, of the increase was in the less than twelve months category. The overall increase in unrealized losses was across most asset classes and reflects higher interest rates at September 30, 2018, compared to December 31, 2017, resulting in generally lower valuations of these fixed maturity securities.

Total unrealized losses greater than twelve months increased by $121,844 from December 31, 2017 to September 30, 2018. Corporate debt securities account for 78%, or $184,445, of the unrealized losses and OTTI greater than twelve months at September 30, 2018. Non-investment grade corporate debt securities account for $6,640 of the unrealized losses and OTTI greater than twelve months. Management does not have the intent to sell these assets; therefore, an OTTI was not recognized in earnings.

Asset-backed and commercial mortgage-backed securities account for 15% of the unrealized losses and OTTI greater than twelve months at September 30, 2018. The present value of the cash flows expected to be collected is not less than amortized cost and management does not have the intent to sell these assets; therefore, an OTTI was not recognized in earnings.

Other-than-temporary impairment recognition — The OTTI on fixed maturity securities where the loss portion is bifurcated and the credit related component is recognized in investment (losses) gains is summarized as follows:



	Three Months Ended September 30,						Nine Months Ended September 30,
	2018			2017			2018			2017
Beginning balance	$	49,683		$	77,411		$	62,231		$	83,665
Reductions:
Due to sales, maturities or payoffs during the period	—			—			(1,510		)	—
Due to increases in cash flows expected to be collected that are recognized over the remaining life of the security	(2,399		)	(5,273		)	(13,437		)	(11,527		)
Ending balance	$	47,284		$	72,138		$	47,284		$	72,138