Investment Securities

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

The following table presents the amortized cost and estimated fair values of investment securities:


	March 31, 2025
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available for Sale	(dollars in thousands)


State and municipal securities	$	958,357	$	—	$	(166,660)	$	791,697
Corporate debt securities	294,686		668		(10,621)		284,733
Collateralized mortgage obligations	1,005,300		11,448		(9,900)		1,006,848
Residential mortgage-backed securities	1,000,882		2,605		(30,135)		973,352
Commercial mortgage-backed securities	611,804		—		(93,391)		518,413

Total	$	3,871,029	$	14,721	$	(310,707)	$	3,575,043

Held to Maturity
Residential mortgage-backed securities	$	640,273	$	1,309	$	(52,213)	$	589,369
Commercial mortgage-backed securities	856,007		—		(135,542)		720,465
Total	$	1,496,280	$	1,309	$	(187,755)	$	1,309,834


	December 31, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available for Sale	(dollars in thousands)


State and municipal securities	$	960,227	$	106	$	(145,446)	$	814,887
Corporate debt securities	313,681		1,123		(14,434)		300,370
Collateralized mortgage obligations	798,157		4,629		(13,901)		788,885
Residential mortgage-backed securities	1,029,846		30		(40,001)		989,875
Commercial mortgage-backed securities	617,605		—		(100,723)		516,882

Total	$	3,719,516	$	5,888	$	(314,505)	$	3,410,899



Held to Maturity
Residential mortgage-backed securities	$	537,856	$	2	$	(60,162)	$	477,696
Commercial mortgage-backed securities	857,713		—		(151,960)		705,753
Total	$	1,395,569	$	2	$	(212,122)	$	1,183,449

In May 2024, the Corporation sold $345.7 million of AFS investment securities and recorded a pre-tax loss of $20.3 million. The proceeds from the sale were reinvested into higher-yielding securities of a similar type and similar duration.

Investment securities carried at $0.4 billion and $0.3 billion at March 31, 2025 and December 31, 2024, respectively, were pledged as collateral to secure public and trust deposits.

The amortized cost and estimated fair values of debt securities as of March 31, 2025, by contractual maturity, are shown in the following table. Actual maturities may differ from contractual maturities because issuers may have the right to call, or borrowers may have the right to prepay, with or without call or prepayment penalties.


		March 31, 2025
		Available for Sale				Held to Maturity
		Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(dollars in thousands)
Due in one year or less		$	13,985	$	13,908	$	—	$	—
Due from one year to five years		105,663		104,052		—		—
Due from five years to ten years		298,517		283,407		—		—
Due after ten years		834,878		675,063		—		—
		1,253,043		1,076,430		—		—
Residential mortgage-backed securities(1)		1,000,882		973,352		640,273		589,369
Commercial mortgage-backed securities(1)		611,804		518,413		856,007		720,465
Collateralized mortgage obligations(1)		1,005,300		1,006,848		—		—
Total		$	3,871,029	$	3,575,043	$	1,496,280	$	1,309,834

(1) Maturities for mortgage-backed securities and collateralized mortgage obligations are dependent upon the interest rate environment and prepayments on the

underlying loans.

The following table presents information related to gross realized gains and losses on the sales of securities for the periods presented:


	Gross Realized Gains		Gross Realized Losses		Net Gains (Losses)
Three months ended	(dollars in thousands)
March 31, 2025	$	663	$	(665)	$	(2)
March 31, 2024	—		—		—

The following tables present the gross unrealized losses and estimated fair values of investment securities aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:


	March 31, 2025
	Less than 12 months					12 months or longer					Total
	Number of Securities	Estimated Fair Value		Unrealized Losses		Number of Securities	Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses

Available for Sale	(dollars in thousands)


State and municipal securities	19	$	45,225	$	(2,451)	277	$	745,510	$	(164,209)	$	790,735	$	(166,660)
Corporate debt securities	1	9,500		(500)		44	251,670		(10,121)		261,170		(10,621)
Collateralized mortgage obligations	5	115,249		(999)		77	83,216		(8,901)		198,465		(9,900)
Residential mortgage-backed securities	19	404,904		(3,632)		69	175,232		(26,503)		580,136		(30,135)
Commercial mortgage-backed securities	1	19,691		(415)		135	498,722		(92,976)		518,413		(93,391)
Total available for sale	45	$	594,569	$	(7,997)	602	$	1,754,350	$	(302,710)	$	2,348,919	$	(310,707)

Held to Maturity
Residential mortgage-backed securities	6	$	122,777	$	(117)	120	$	299,666	$	(52,096)	$	422,443	$	(52,213)
Commercial mortgage-backed securities	—	—		—		60	720,465		(135,542)		720,465		(135,542)
Total held to maturity	6	$	122,777	$	(117)	180	$	1,020,131	$	(187,638)	$	1,142,908	$	(187,755)


	December 31, 2024
	Less than 12 months					12 months or longer					Total
	Number of Securities	Estimated Fair Value		Unrealized Losses		Number of Securities	Estimated Fair Value		Unrealized Losses		Estimated Fair Value		Unrealized Losses
Available for Sale	(dollars in thousands)


State and municipal securities	22	$	53,026	$	(1,692)	272	$	755,310	$	(143,754)	$	808,336	$	(145,446)
Corporate debt securities	1	4,844		(13)		47	264,099		(14,421)		268,943		(14,434)
Collateralized mortgage obligations	12	288,871		(3,463)		77	85,485		(10,438)		374,356		(13,901)
Residential mortgage-backed securities	42	777,695		(9,178)		69	174,284		(30,823)		951,979		(40,001)
Commercial mortgage-backed securities	1	19,291		(875)		135	497,591		(99,848)		516,882		(100,723)
Total available for sale	78	$	1,143,727	$	(15,221)	600	$	1,776,769	$	(299,284)	$	2,920,496	$	(314,505)

Held to Maturity

Residential mortgage-backed securities	7	$	155,726	$	(1,754)	120	$	303,220	$	(58,408)	$	458,946	$	(60,162)
Commercial mortgage-backed securities	—	—		—		60	705,753		(151,960)		705,753		(151,960)
Total held to maturity	7	$	155,726	$	(1,754)	180	$	1,008,973	$	(210,368)	$	1,164,699	$	(212,122)

The Corporation's collateralized mortgage obligations, residential mortgage-backed securities and commercial mortgage-backed securities have contractual terms that generally do not permit the issuer to settle the securities at a price less than the amortized cost of the investment. The change in fair value of these securities is attributable to changes in interest rates and not credit quality. In addition, these securities have principal payments that are guaranteed by U.S. government-sponsored agencies. Therefore, the Corporation did not record an ACL for these securities as of March 31, 2025 and December 31, 2024. The Corporation does not have the intent to sell, and does not believe it will more likely than not be required to sell, any of these securities prior to a recovery of their fair value to amortized cost.

Based on the payment status and management's evaluation of the Corporation's state and municipal securities, no ACL was required for these securities as of March 31, 2024 and December 31, 2024. The Corporation does not have the intent to sell, and does not believe it will more likely than not be required to sell, any of these securities prior to a recovery of their fair value to amortized cost, which may be at maturity.

The majority of the corporate debt securities were rated at or above investment grade as of March 31, 2025 and December 31, 2024. Based on the payment status, rating and management's evaluation of these securities, no ACL was required for corporate debt securities as of March 31, 2025 and December 31, 2024. The Corporation does not have the intent to sell, and does not believe it will more likely than not to be required to sell, any of these securities prior to a recovery of their fair value to amortized cost, which may be at maturity.