Investment Securities Available for Sale (Tables)

9 Months Ended

Sep. 30, 2022

Summary of Available-for-Sale Investment Securities

The amortized cost, gross unrealized gains and losses, and estimated fair values of investment securities available for sale at September 30, 2022 and December 31, 2021 are summarized below.


	September 30, 2022
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	515,190	$	—	$	(47,434)	$	467,756
U.S. Government agency securities	52,411		1		(3,842)		48,570
Mortgage-backed securities issued by U.S. Government agencies	840,735		—		(118,123)		722,612
Mortgage-backed securities issued by U.S. Government sponsored enterprises	8,174,641		—		(1,341,702)		6,832,939
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	791,310		—		(106,802)		684,508
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	884,027		—		(71,032)		812,995

Corporate debt securities and other debt securities	18,382		—		(254)		18,128
Total investment securities available for sale	$	11,276,696	$	1	$	(1,689,189)	$	9,587,508

	December 31, 2021
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
U.S. Treasury securities	$	120,465	$	—	$	(2,627)	$	117,838
U.S. Government agency securities	53,214		1,374		(387)		54,201
Mortgage-backed securities issued by U.S. Government agencies	790,329		768		(11,464)		779,633
Mortgage-backed securities issued by U.S. Government sponsored enterprises	8,063,890		50,491		(102,080)		8,012,301
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	951,691		4,658		(16,726)		939,623
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	479,420		8,644		(6,320)		481,744
Asset-backed securities	514,188		—		—		514,188
Corporate debt securities and other debt securities	18,309		492		—		18,801
Total investment securities available for sale	$	10,991,506	$	66,427	$	(139,604)	$	10,918,329

Schedule of Gross Unrealized Losses on Investment Securities and Fair Value

Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at September 30, 2022 and December 31, 2021 are presented below.


	September 30, 2022
	Less than 12 Months				12 Months or Longer				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury securities	$	359,580	$	(31,435)	$	83,875	$	(15,999)	$	443,455	$	(47,434)
U.S. Government agency securities	48,311		(3,842)		—		—		48,311		(3,842)
Mortgage-backed securities issued by U.S. Government agencies	220,484		(12,059)		502,128		(106,064)		722,612		(118,123)
Mortgage-backed securities issued by U.S. Government sponsored enterprises	2,371,537		(331,934)		4,461,403		(1,009,768)		6,832,940		(1,341,702)
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	171,343		(13,315)		513,165		(93,487)		684,508		(106,802)
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	682,610		(40,538)		130,385		(30,494)		812,995		(71,032)
Corporate debt securities and other debt securities	18,128		(254)		—		—		18,128		(254)
Total	$	3,871,993	$	(433,377)	$	5,690,956	$	(1,255,812)	$	9,562,949	$	(1,689,189)

	December 31, 2021
	Less than 12 Months				12 Months or Longer				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury securities	$	49,648	$	(379)	$	47,590	$	(2,248)	$	97,238	$	(2,627)
U.S. Government agency securities	21,760		(387)		—		—		21,760		(387)
Mortgage-backed securities issued by U.S. Government agencies	461,078		(5,858)		244,264		(5,606)		705,342		(11,464)
Mortgage-backed securities issued by U.S. Government sponsored enterprises	5,729,476		(82,671)		643,758		(19,409)		6,373,234		(102,080)
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	187,431		(3,981)		504,238		(12,745)		691,669		(16,726)
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	146,672		(2,951)		83,533		(3,369)		230,205		(6,320)
Total	$	6,596,065	$	(96,227)	$	1,523,383	$	(43,377)	$	8,119,448	$	(139,604)

Amortized Cost and Estimated Fair Value by Contractual Maturity of Investment Securities Available-for-Sale

For purposes of the maturity table, MBSs and CMOs, which are not due at a single maturity date, have been classified based on the final contractual maturity date.


	Distribution of Maturities at September 30, 2022
(in thousands)	Within One Year		1 to 5 Years		5 to 10 Years		More Than 10 Years		Total
Amortized Cost
U.S. Treasury securities	$	24,100	$	392,854	$	98,236	$	—	$	515,190
U.S. Government agency securities	273		22,148		29,990		—		52,411
Mortgage-backed securities issued by U.S. Government agencies	—		621		4		840,110		840,735
Mortgage-backed securities issued by U.S. Government sponsored enterprises	—		5,062		115,479		8,054,100		8,174,641
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	—		102		—		791,208		791,310
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	—		486,500		330,378		67,149		884,027

Corporate debt securities and other debt securities	9,500		—		8,882		—		18,382
Total amortized cost	$	33,873	$	907,287	$	582,969	$	9,752,567	$	11,276,696

Fair Value
U.S. Treasury securities	$	24,100	$	358,045	$	85,611	$	—	$	467,756
U.S. Government agency securities	273		19,415		28,882		—		48,570
Mortgage-backed securities issued by U.S. Government agencies	—		597		4		722,011		722,612
Mortgage-backed securities issued by U.S. Government sponsored enterprises	—		4,706		107,107		6,721,126		6,832,939
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	—		100		—		684,408		684,508
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises	—		460,412		289,991		62,592		812,995

Corporate debt securities and other debt securities	9,457		—		8,671		—		18,128
Total fair value	$	33,830	$	843,275	$	520,266	$	8,190,137	$	9,587,508

Schedule of Sales Activities of Available-for-Sale Securities

Gross gains and gross losses on sales of securities available for sale for the three and nine months ended September 30, 2022 and 2021 are presented below. The specific identification method is used to reclassify gains and losses out of other comprehensive income (loss) at the time of sale.


	Three Months Ended September 30,				Nine Months Ended September 30,
(in thousands)	2022		2021		2022		2021
Gross realized gains on sales	$	—	$	962	$	—	$	962
Gross realized losses on sales	—		—		—		(1,990)
Investment securities gains (losses), net	$	—	$	962	$	—	$	(1,028)