Investment Securities

6 Months Ended

Jun. 30, 2023

Investments, Debt and Equity Securities [Abstract]

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


	June 30, 2024
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available for Sale	(dollars in thousands)


State and municipal securities	$	965,392	$	50	$	(145,333)	$	820,109
Corporate debt securities	368,901		510		(32,013)		337,398
Collateralized mortgage obligations	724,602		1,533		(12,366)		713,769
Residential mortgage-backed securities	589,267		14		(32,090)		557,191
Commercial mortgage-backed securities	610,960		—		(99,833)		511,127

Total	$	3,259,122	$	2,107	$	(321,635)	$	2,939,594

Held to Maturity
Residential mortgage-backed securities	$	384,956	$	—	$	(58,593)	$	326,363
Commercial mortgage-backed securities	859,477		—		(152,401)		707,076
Total	$	1,244,433	$	—	$	(210,994)	$	1,033,439


	December 31, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available for Sale	(dollars in thousands)
U.S. Government securities	$	42,475	$	—	$	(314)	$	42,161
U.S. Government-sponsored agency securities	1,038		—		(28)		1,010
State and municipal securities	1,200,571		1,089		(129,647)		1,072,013
Corporate debt securities	480,714		473		(40,636)		440,551
Collateralized mortgage obligations	122,824		—		(11,390)		111,434
Residential mortgage-backed securities	223,273		7		(26,485)		196,795
Commercial mortgage-backed securities	627,364		—		(92,976)		534,388

Total	$	2,698,259	$	1,569	$	(301,476)	$	2,398,352



Held to Maturity
Residential mortgage-backed securities	$	407,075	$	—	$	(51,805)	$	355,270
Commercial mortgage-backed securities	860,847		—		(143,910)		716,937
Total	$	1,267,922	$	—	$	(195,715)	$	1,072,207

In May 2024, the Corporation sold $345.7 million AFS 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.

Securities carried at $1.2 billion and $0.4 billion at June 30, 2024 and December 31, 2023, respectively, were pledged as collateral to secure public and trust deposits.

The amortized cost and estimated fair values of debt securities as of June 30, 2024, by contractual maturity, are shown in the following table. Actual maturities may differ from contractual maturities because borrowers may have the right to call or prepay with or without call or prepayment penalties.


		June 30, 2024
		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		$	13,762	$	13,533	$	—	$	—
Due from one year to five years		110,303		106,430		—		—
Due from five years to ten years		362,563		327,817		—		—
Due after ten years		847,665		709,727		—		—
		1,334,293		1,157,507		—		—
Residential mortgage-backed securities(1)		589,267		557,191		384,956		326,363
Commercial mortgage-backed securities(1)		610,960		511,127		859,477		707,076
Collateralized mortgage obligations(1)		724,602		713,769		—		—
Total		$	3,259,122	$	2,939,594	$	1,244,433	$	1,033,439

(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:


	Gross Realized Gains		Gross Realized Losses		Net Gains (Losses)
Three months ended	(dollars in thousands)
June 30, 2024	$	91	$	(20,373)	$	(20,282)
June 30, 2023	—		(4)		(4)

Six months ended
June 30, 2024	$	91	$	(20,373)	$	(20,282)
June 30, 2023	283		(264)		19

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:


	June 30, 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	19	$	48,682	$	(1,552)	276	$	766,484	$	(143,781)	$	815,166	$	(145,333)
Corporate debt securities	—	—		—		52	286,277		(32,013)		286,277		(32,013)
Collateralized mortgage obligations	9	195,411		(601)		82	93,219		(11,765)		288,630		(12,366)
Residential mortgage-backed securities	32	369,024		(1,115)		75	183,416		(30,975)		552,440		(32,090)
Commercial mortgage-backed securities	—	—		—		135	511,127		(99,833)		511,127		(99,833)
Total available for sale	60	$	613,117	$	(3,268)	620	$	1,840,523	$	(318,367)	$	2,453,640	$	(321,635)

Held to Maturity
Residential mortgage-backed securities	—	$	—	$	—	120	$	326,363	$	(58,593)	$	326,363	$	(58,593)
Commercial mortgage-backed securities	—	—		—		60	707,076		(152,401)		707,076		(152,401)
Total held to maturity	—	$	—	$	—	180	$	1,033,439	$	(210,994)	$	1,033,439	$	(210,994)


	December 31, 2023
	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)
U.S. Government Securities	—	$	—	$	—	1	$	42,161	$	(314)	$	42,161	$	(314)
U.S. Government-sponsored agency securities	—	—		—		1	1,010		(28)		1,010		(28)
State and municipal securities	40	76,155		(858)		314	917,274		(128,789)		993,429		(129,647)
Corporate debt securities	8	42,945		(1,326)		60	370,523		(39,310)		413,468		(40,636)
Collateralized mortgage obligations	—	—		—		93	111,434		(11,390)		111,434		(11,390)
Residential mortgage-backed securities	6	409		(3)		69	195,453		(26,482)		195,862		(26,485)
Commercial mortgage-backed securities	2	26,907		(1,053)		133	507,481		(91,923)		534,388		(92,976)
Total available for sale	56	$	146,416	$	(3,240)	671	$	2,145,336	$	(298,236)	$	2,291,752	$	(301,476)

Held to Maturity

Residential mortgage-backed securities	—	$	—	$	—	120	$	355,270	$	(51,805)	$	355,270	$	(51,805)
Commercial mortgage-backed securities	—	—		—		60	716,937		(143,910)		716,937		(143,910)
Total held to maturity	—	$	—	$	—	180	$	1,072,207	$	(195,715)	$	1,072,207	$	(195,715)

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. 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. Therefore, the Corporation did not record a loss on these investments as of June 30, 2024 and December 31, 2023.

As of June 30, 2024 and December 31, 2023, no ACL was required for the Corporation's state and municipal securities. 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. Therefore, the Corporation did not record a loss on these investments as of June 30, 2024 and December 31, 2023.

The majority of the corporate debt securities were rated at or above investment grade as of June 30, 2024 and December 31, 2023. Based on the payment status, rating and management's evaluation of these securities, no ACL was required for corporate debt securities as of June 30, 2024 and December 31, 2023. 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. Therefore, the Corporation did not record a loss on these investments as of June 30, 2024 and December 31, 2023.