
(in thousands)	Amortized Cost(1)		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
June 30, 2024
Available-for-sale debt securities:
U.S. Treasury securities	$	403,641	$	—	$	(15,483)	$	388,158
U.S. government agency securities	125,000		—		(18,791)		106,209
Residential mortgage-backed securities	3,307,715		6,277		(337,456)		2,976,536


CRT securities	13,136		—		(808)		12,328
Total available-for-sale debt securities	3,849,492		6,277		(372,538)		3,483,231
Held-to-maturity debt securities:
Residential mortgage-backed securities	831,513		—		(112,603)		718,910
Total held-to-maturity debt securities	831,513		—		(112,603)		718,910
Equity securities							74,232
Total investment securities(2)							$	4,388,976
December 31, 2023
Available-for-sale debt securities:
U.S. Treasury securities	$	651,112	$	—	$	(14,639)	$	636,473
U.S. government agency securities	125,000		—		(18,408)		106,592
Residential mortgage-backed securities	2,782,734		540		(312,442)		2,470,832


CRT securities	13,636		—		(1,641)		11,995
Total available-for-sale debt securities	3,572,482		540		(347,130)		3,225,892
Held-to-maturity securities:
Residential mortgage-backed securities	865,477		—		(101,633)		763,844
Total held-to-maturity securities	865,477		—		(101,633)		763,844
Equity securities							51,825
Total investment securities(2)							$	4,143,194

(1) Excludes accrued interest receivable of $12.0 million and $9.5 million at June 30, 2024 and December 31, 2023, respectively, related to available-for-sale debt securities and $1.3 million and $1.4 million at June 30, 2024 and December 31, 2023, respectively, related to held-to-maturity debt securities that is recorded in accrued interest receivable and other assets on the consolidated balance sheets.

The amortized cost and estimated fair value as of June 30, 2024, excluding accrued interest receivable, of available-for-sale and held-to-maturity debt securities are presented below by contractual maturity. Actual maturities may differ from contractual maturities of mortgage-backed securities because borrowers may have the right to call or prepay obligations with or without prepayment penalties.


	Available-for-sale				Held-to-maturity
(in thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value

Due within one year	$	—	$	—	$	—	$	—
Due after one year through five years	453,642		432,220		—		—
Due after five years through ten years	105,433		89,394		—		—
Due after ten years	3,290,417		2,961,617		831,513		718,910
Total	$	3,849,492	$	3,483,231	$	831,513	$	718,910

The table below presents the weighted average yields for the Company’s available-for-sale debt securities for the six months ended June 30, 2024. Weighted average yields are calculated based on amortized cost on a tax-exempt basis assuming a 21% federal tax rate, where applicable.


	U.S. Treasury securities		U.S. government agency securities		Residential mortgage-backed securities		CRT securities
Due within one year	—	%	—	%	—	%	—	%
Due after one year through five years	2.71		1.00		—		—
Due after five years through ten years	—		1.21		1.25		5.46
Due after ten years	—		—		3.36		—
Total	2.71	%	1.13	%	3.35	%	5.46	%


	Less Than 12 Months				12 Months or Longer				Total
(in thousands)	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
June 30, 2024
U.S. Treasury securities	$	—	$	—	$	388,158	$	(15,483)	$	388,158	$	(15,483)
U.S. government agency securities	—		—		106,209		(18,791)		106,209		(18,791)
Residential mortgage-backed securities	335,741		(4,305)		2,272,460		(333,151)		2,608,201		(337,456)
CRT securities	—		—		12,328		(808)		12,328		(808)
Total	$	335,741	$	(4,305)	$	2,779,155	$	(368,233)	$	3,114,896	$	(372,538)
December 31, 2023
U.S. Treasury securities	$	—	$	—	$	636,473	$	(14,639)	$	636,473	$	(14,639)
U.S. government agency securities	—		—		106,592		(18,408)		106,592		(18,408)
Residential mortgage-backed securities	910,999		(19,751)		1,501,340		(292,691)		2,412,339		(312,442)
CRT securities	—		—		11,995		(1,641)		11,995		(1,641)
Total	$	910,999	$	(19,751)	$	2,256,400	$	(327,379)	$	3,167,399	$	(347,130)

At June 30, 2024, the Company had 108 available-for-sale debt securities in an unrealized loss position, comprised of 10 U.S. Treasury securities, five U.S. government agency securities, 91 residential mortgage-backed securities and two CRT securities. The unrealized losses on the available-for-sale debt securities were the result of changes in market interest rates compared to the date the securities were acquired rather than the credit quality of the issuers or underlying loans. The Company does not currently intend to sell and based on current conditions it does not believe it is likely that the Company will be required to sell these available-for-sale debt securities before recovery of the amortized cost of such securities in an unrealized loss position and has therefore recorded the unrealized losses related to this portfolio in accumulated other comprehensive income/(loss), net (“AOCI”). Held-to-maturity securities consist of government guaranteed securities for which no loss is expected. At June 30, 2024 and December 31, 2023, no allowance for credit losses was established for available-for-sale or held-to-maturity debt securities.

Equity securities consist of investments that qualify for consideration under the regulations implementing the Community Reinvestment Act and investments in exchange traded funds. The following is a summary of unrealized and realized gains/(losses) recognized on equity securities included in other non-interest income on the consolidated statements of income and other comprehensive income:



	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2024		2023		2024		2023
Net gains/(losses) recognized during the period	$	(59)	$	951	$	3,975	$	2,196
Less: Realized net gains/(losses) recognized on securities sold	59		(10)		371		(606)
Unrealized net gains/(losses) recognized on securities still held	$	(118)	$	961	$	3,604	$	2,802