The following table summarizes the amortized cost and fair value of AFS securities by major type:


	At December 31, 2022
(In thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury notes	$	755,968	$	—	$	(38,928)	$	717,040
Government agency debentures	302,018		—		(43,644)		258,374
Municipal bonds and notes	1,719,110		5		(85,913)		1,633,202
Agency CMO	64,984		—		(5,019)		59,965
Agency MBS	2,461,337		26		(303,339)		2,158,024
Agency CMBS	1,664,600		—		(258,114)		1,406,486
CMBS	929,588		—		(32,948)		896,640
CLO	2,108		—		(1)		2,107
Corporate debt	795,999		—		(91,587)		704,412
Private label MBS	48,895		—		(4,646)		44,249
Other	12,548		—		(350)		12,198
Total AFS securities	$	8,757,155	$	31	$	(864,489)	$	7,892,697

	At December 31, 2021
(In thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
U.S. Treasury notes	$	398,664	$	—	$	(1,698)	$	396,966
Agency CMO	88,109		2,326		(51)		90,384
Agency MBS	1,568,293		36,130		(11,020)		1,593,403
Agency CMBS	1,248,548		2,537		(18,544)		1,232,541
CMBS	887,640		506		(1,883)		886,263
CLO	21,860		—		(13)		21,847
Corporate debt	14,583		—		(1,133)		13,450
Total AFS securities	$	4,227,697	$	41,499	$	(34,342)	$	4,234,854

Accrued interest receivable on AFS securities of $36.9 million and $7.5 million at December 31, 2022, and 2021, respectively, is excluded from amortized cost and is reported in Accrued interest receivable and other assets on the accompanying Consolidated Balance Sheets.

The following tables summarize the gross unrealized losses and fair value of AFS securities by length of time each major security type has been in a continuous unrealized loss position:


	At December 31, 2022
	Less Than 12 Months				12 Months or More				Total
(Dollars in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Number of Holdings	Fair Value		Unrealized Losses
U.S. Treasury notes	$	337,563	$	(19,167)	$	379,477	$	(19,761)	23	$	717,040	$	(38,928)
Government agency debentures	258,374		(43,644)		—		—		19	258,374		(43,644)
Municipal bonds and notes	1,616,771		(85,913)		—		—		444	1,616,771		(85,913)
Agency CMO	55,693		(4,640)		4,272		(379)		39	59,965		(5,019)
Agency MBS	1,641,544		(206,412)		515,206		(96,927)		460	2,156,750		(303,339)
Agency CMBS	485,333		(68,674)		921,153		(189,440)		132	1,406,486		(258,114)
CMBS	273,150		(8,982)		598,490		(23,966)		52	871,640		(32,948)
CLO	—		—		2,107		(1)		1	2,107		(1)
Corporate debt	692,990		(89,692)		8,421		(1,895)		105	701,411		(91,587)
Private label MBS	44,249		(4,646)		—		—		3	44,249		(4,646)
Other	12,198		(350)		—		—		4	12,198		(350)
Total AFS securities in an unrealized loss position	$	5,417,865	$	(532,120)	$	2,429,126	$	(332,369)	1,282	$	7,846,991	$	(864,489)


	At December 31, 2021
	Less Than 12 Months				12 Months or More				Total
(Dollars in thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Number of Holdings	Fair Value		Unrealized Losses
U.S. Treasury notes	$	396,966	$	(1,698)	$	—	$	—	8	$	396,966	$	(1,698)
Agency CMO	7,895		(51)		—		—		2	7,895		(51)
Agency MBS	506,602		(7,354)		110,687		(3,666)		70	617,289		(11,020)
Agency CMBS	632,213		(6,163)		335,480		(12,381)		28	967,693		(18,544)
CMBS	724,762		(1,744)		81,253		(139)		50	806,015		(1,883)
CLO	—		—		21,848		(13)		1	21,848		(13)
Corporate debt	4,203		(76)		9,247		(1,057)		3	13,450		(1,133)
Total AFS securities in an unrealized loss position	$	2,272,641	$	(17,086)	$	558,515	$	(17,256)	162	$	2,831,156	$	(34,342)

The Company assesses each AFS security that is in an unrealized loss position to determine whether the decline in fair value below the amortized cost basis is attributable to credit or other factors. The $830.1 million increase in gross unrealized losses from December 31, 2021, to December 31, 2022, is primarily due to higher market rates. Market prices will approach par as the securities approach maturity.

At December 31, 2022, the Company had the intent to hold its AFS securities with unrealized loss positions through the anticipated recovery period, and it is more-likely-than-not that the Company would not have to sell these AFS securities before the recovery of their amortized cost basis. The issuers of these AFS securities have not, to the Company’s knowledge, established any cause for default. Therefore, the Company expects to recover the entire amortized cost basis. Accordingly, there were no AFS securities in non-accrual status and no ACL recorded on AFS securities at December 31, 2022, and 2021.

The following table summarizes the amortized cost and fair value of AFS securities by contractual maturity:


	At December 31, 2022
(In thousands)	Amortized Cost		Fair Value
Maturing within 1 year	$	204,757	$	198,765
After 1 year through 5 years	1,200,088		1,127,769
After 5 years through 10 years	1,459,962		1,351,397
After 10 years	5,892,348		5,214,766
Total AFS securities	$	8,757,155	$	7,892,697

AFS securities that are not due at a single maturity date have been categorized based on the maturity date of the underlying collateral. Actual principal cash flows may differ from this categorization as borrowers have the right to repay their obligations with or without prepayment penalties.


	Years ended December 31,
(In thousands)	2022		2021		2020
Proceeds from sales	$	172,947	$	—	$	8,963

Gross realized gains	$	—	$	—	$	8
Gross realized losses	6,751		—		—
(Loss) gain on sale of investment securities, net	$	(6,751)	$	—	$	8


	At December 31,
(In thousands)	2022		2021
AFS securities pledged for deposits, at fair value	$	2,573,072	$	855,323
AFS securities pledged for borrowings and other, at fair value	1,195,101		924,841
Total AFS securities pledged	$	3,768,173	$	1,780,164


	At December 31, 2022
(In thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Allowance		Net Carrying Value
Agency CMO	$	28,358	$	—	$	(2,060)	$	26,298	$	—	$	28,358
Agency MBS	2,626,114		827		(339,592)		2,287,349		—		2,626,114
Agency CMBS	2,831,949		845		(407,648)		2,425,146		—		2,831,949
Municipal bonds and notes	928,845		1,098		(47,183)		882,760		182		928,663
CMBS	149,613		—		(9,713)		139,900		—		149,613
Total HTM securities	$	6,564,879	$	2,770	$	(806,196)	$	5,761,453	$	182	$	6,564,697

	At December 31, 2021
(In thousands)	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value		Allowance		Net Carrying Value
Agency CMO	$	42,405	$	655	$	(25)	$	43,035	$	—	$	42,405
Agency MBS	2,901,593		71,444		(11,788)		2,961,249		—		2,901,593
Agency CMBS	2,378,475		11,202		(43,844)		2,345,833		—		2,378,475
Municipal bonds and notes	705,918		51,572		—		757,490		214		705,704
CMBS	169,948		3,381		—		173,329		—		169,948
Total HTM securities	$	6,198,339	$	138,254	$	(55,657)	$	6,280,936	$	214	$	6,198,125

Accrued interest receivable on HTM securities of $24.2 million and $21.2 million at December 31, 2022, and 2021, respectively, is excluded from amortized cost and is reported in Accrued interest receivable and other assets on the accompanying Consolidated Balance Sheets.

An ACL on HTM securities is recorded for certain Municipal bonds and notes to account for expected lifetime credit losses. Agency securities represent obligations issued by a U.S. government-sponsored enterprise or other federally-related entity and are either explicitly or implicitly guaranteed and therefore, assumed to be zero loss. HTM securities with gross unrealized losses and no ACL are considered to be of high credit quality. Therefore, zero credit loss is recorded at December 31, 2022, and 2021.

The following table summarizes the activity in the ACL on HTM securities:


	Years ended December 31,
(In thousands)	2022		2021		2020
Balance, beginning of period	$	214	$	299	$	—
Adoption of CECL	—		—		397
(Benefit) for credit losses	(32)		(85)		(98)
Balance, end of period	$	182	$	214	$	299


	At December 31, 2022
(In thousands)	Amortized Cost		Fair Value
Maturing within 1 year	$	2,195	$	2,194
After 1 year through 5 years	53,632		54,275
After 5 years through 10 years	329,156		312,741
After 10 years	6,179,896		5,392,243
Total HTM securities	$	6,564,879	$	5,761,453

HTM securities that are not due at a single maturity date have been categorized based on the maturity date of the underlying collateral. Actual principal cash flows may differ from this categorization as borrowers have the right to prepay their obligations with or without prepayment penalties.

The Company monitors the credit quality of HTM securities through credit ratings provided by S&P, Moody's, Fitch Ratings, Inc., Kroll Bond Rating Agency, or DBRS Inc. Credit ratings express opinions about the credit quality of a security, and are updated at each quarter end. Investment grade securities are rated BBB- or higher by S&P, or Baa3 or higher by Moody's, and are generally considered by the rating agencies and market participants to be of low credit risk. Conversely, securities rated below investment grade, which are labeled as speculative grade by the rating agencies, are considered to have distinctively higher credit risk than investment grade securities. There were no speculative grade HTM securities at December 31, 2022, and 2021. HTM securities that are not rated are collateralized with U.S. Treasury obligations.


	At December 31, 2022
	Investment Grade
(In thousands)	Aaa		Aa1		Aa2		Aa3		A1		A2		Baa2		Not Rated
Agency CMOs	$	—	$	28,358	$	—	$	—	$	—	$	—	$	—	$	—
Agency MBS	—		2,626,114		—		—		—		—		—		—
Agency CMBS	—		2,831,949		—		—		—		—		—		—
Municipal bonds and notes	336,035		163,312		255,235		116,870		38,177		4,165		—		15,051
CMBS	149,613		—		—		—		—		—		—		—
Total HTM securities	$	485,648	$	5,649,733	$	255,235	$	116,870	$	38,177	$	4,165	$	—	$	15,051


	At December 31, 2021
	Investment Grade
(In thousands)	Aaa		Aa1		Aa2		Aa3		A1		A2		Baa2		Not Rated
Agency CMOs	$	—	$	42,405	$	—	$	—	$	—	$	—	$	—	$	—
Agency MBS	—		2,901,593		—		—		—		—		—		—
Agency CMBS	—		2,378,475		—		—		—		—		—		—
Municipal bonds and notes	207,426		119,804		227,106		104,232		35,878		8,260		95		3,117
CMBS	169,948		—		—		—		—		—		—		—
Total HTM securities	$	377,374	$	5,442,277	$	227,106	$	104,232	$	35,878	$	8,260	$	95	$	3,117

At December 31, 2022, and 2021, there were no HTM debt securities past due under the terms of their agreements or in
non-accrual status.


	At December 31,
(In thousands)	2022		At	2021
HTM securities pledged for deposits, at amortized cost	$	1,596,777		$	1,834,117
HTM securities pledged for borrowings and other, at amortized cost	260,735			1,243,139
Total HTM securities pledged	$	1,857,512		$	3,077,256