INVESTMENT SECURITIES

3 Months Ended

Mar. 31, 2024

Investments, Debt and Equity Securities [Abstract]

The following table summarizes the amortized cost, gross unrealized gains and losses and approximate fair value of investment securities available for sale as of March 31, 2024 and December 31, 2023.


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available for sale at March 31, 2024

U.S. Government-sponsored agency securities	$	110,457	$	—	$	17,325	$	93,132
State and municipal	1,179,288		27		136,252		1,043,063
U.S. Government-sponsored mortgage-backed securities	565,177		336		93,469		472,044
Corporate obligations	12,950		—		976		11,974

Total available for sale	$	1,867,872	$	363	$	248,022	$	1,620,213


	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Available for sale at December 31, 2023

U.S. Government-sponsored agency securities	$	111,521	$	—	$	16,214	$	95,307
State and municipal	1,181,029		364		116,222		1,065,171
U.S. Government-sponsored mortgage-backed securities	541,343		462		86,990		454,815
Corporate obligations	12,947		—		1,128		11,819

Total available for sale	$	1,846,840	$	826	$	220,554	$	1,627,112

The following table summarizes the amortized cost, gross unrealized gains and losses, approximate fair value and allowance for credit losses on investment securities held to maturity as of March 31, 2024 and December 31, 2023.


	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Held to maturity at March 31, 2024
U.S. Government-sponsored agency securities	$	370,310	$	—	$	370,310	$	—	$	66,154	$	304,156
State and municipal	1,097,848		245		1,097,603		691		171,353		927,186
U.S. Government-sponsored mortgage-backed securities	693,948		—		693,948		—		106,317		587,631
Foreign investment	1,500		—		1,500		—		22		1,478
Total held to maturity	$	2,163,606	$	245	$	2,163,361	$	691	$	343,846	$	1,820,451


	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Held to maturity at December 31, 2023
U.S. Government-sponsored agency securities	$	374,002	$	—	$	374,002	$	—	$	64,159	$	309,843
State and municipal	1,099,201		245		1,098,956		1,625		152,113		948,713
U.S. Government-sponsored mortgage-backed securities	709,794		—		709,794		—		99,448		610,346
Foreign investment	1,500		—		1,500		—		28		1,472
Total held to maturity	$	2,184,497	$	245	$	2,184,252	$	1,625	$	315,748	$	1,870,374

Accrued interest on investment securities available for sale and held to maturity at March 31, 2024 and December 31, 2023 of $22.6 million and $25.2 million, respectively, are included in the Interest Receivable line on the Corporation's Consolidated Condensed Balance Sheets. The total amount of accrued interest is excluded from the amortized cost of available for sale and held to maturity securities presented above.

In determining the allowance for credit losses on investment securities available for sale that are in an unrealized loss position, the Corporation first assesses whether it intends to sell, or it is more likely than not that it will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value through the income statement. For investment securities available for sale that do not meet the aforementioned criteria, the Corporation evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, the Corporation considers the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized cost basis. Unrealized losses that have not been recorded through an allowance for credit losses is recognized in other comprehensive income. Adjustments to the allowance are reported in the income statement as a component of the provision for credit loss. The Corporation has made the accounting policy election to exclude accrued interest receivable on investment securities available for sale from the estimate of credit losses. Investment securities available for sale are charged off against the allowance or, in the absence of any allowance, written down through the income statement when deemed uncollectible or when either of the aforementioned criteria regarding intent or requirement to sell is met. The Corporation did not record an allowance for credit losses on its investment securities available for sale as the unrealized losses were attributable to changes in interest rates, not credit quality.

The allowance for credit losses on investment securities held to maturity is a contra asset-valuation account that is deducted from the amortized cost basis of investment securities held to maturity to present the net amount expected to be collected. Investment securities held to maturity are charged off against the allowance when deemed uncollectible. Adjustments to the allowance are reported in the income statement as a component of the provision for credit loss. The Corporation measures expected credit losses on investment securities held to maturity on a collective basis by major security type with each type sharing similar risk characteristics, and considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. The Corporation has made the accounting policy election to exclude accrued interest receivable on investment securities held to maturity from the estimate of credit losses. With regard to U.S. Government-sponsored agency and mortgage-backed securities, all these securities are issued by a U.S. Government-sponsored entity and have an implicit or explicit government guarantee; therefore, no allowance for credit losses has been recorded for these securities. With regard to securities issued by states and municipalities and other investment securities held to maturity, management considers (1) issuer bond ratings, (2) historical loss rates for given bond ratings, (3) the financial condition of the issuer, and (4) whether issuers continue to make timely principal and interest payments under the contractual terms of the securities. Historical loss rates associated with securities having similar grades as those in the Corporation's portfolio have been insignificant. Furthermore, as of March 31, 2024, there were no past due principal and interest payments associated with these securities. At current expected credit loss ("CECL") adoption, an allowance for credit losses of $245,000 was recorded on the state and municipal securities classified as held to maturity based on applying the long-term historical credit loss rate, as published by Moody’s, for similarly rated securities. The balance of the allowance for credit losses remained unchanged at $245,000 as of March 31, 2024.

On a quarterly basis, the Corporation monitors the credit quality of investment securities held to maturity through the use of credit ratings. The following table summarizes the amortized cost of investment securities held to maturity at March 31, 2024, aggregated by credit quality indicator.


	Held to Maturity
	State and municipal		Other		Total
Credit Rating:
Aaa	$	114,449	$	70,587	$	185,036
Aa1	159,923		—		159,923
Aa2	169,157		—		169,157
Aa3	133,379		—		133,379
A1	131,318		—		131,318
A2	16,837		—		16,837
A3	3,468		—		3,468

Non-rated	369,317		995,171		1,364,488
Total	$	1,097,848	$	1,065,758	$	2,163,606

The following tables summarize, as of March 31, 2024 and December 31, 2023, investment securities available for sale in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by security type and length of time in a continuous unrealized loss position.


	Less than 12 Months				12 Months or Longer				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Investment securities available for sale at March 31, 2024

U.S. Government-sponsored agency securities	$	—	$	—	$	93,132	$	17,325	$	93,132	$	17,325
State and municipal	54,062		1,643		980,756		134,609		1,034,818		136,252
U.S. Government-sponsored mortgage-backed securities	43,251		499		408,518		92,970		451,769		93,469
Corporate obligations	—		—		11,944		976		11,944		976
Total investment securities available for sale	$	97,313	$	2,142	$	1,494,350	$	245,880	$	1,591,663	$	248,022


	Less than 12 Months				12 Months or Longer				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Investment securities available for sale at December 31, 2023

U.S. Government-sponsored agency securities	$	—	$	—	$	95,307	$	16,214	$	95,307	$	16,214
State and municipal	55,514		1,076		963,584		115,146		1,019,098		116,222
U.S. Government-sponsored mortgage-backed securities	11,493		25		422,868		86,965		434,361		86,990
Corporate obligations	—		—		11,788		1,128		11,788		1,128
Total investment securities available for sale	$	67,007	$	1,101	$	1,493,547	$	219,453	$	1,560,554	$	220,554

The following table summarizes investment securities available for sale in an unrealized loss position for which an allowance for credit losses has not been recorded, aggregated by security type and the number of securities in the portfolio as of the dates indicated.


	Gross Unrealized Losses		Number of Securities
Investment securities available for sale at March 31, 2024

U.S. Government-sponsored agency securities	$	17,325	14
State and municipal	136,252		721
U.S. Government-sponsored mortgage-backed securities	93,469		156
Corporate obligations	976		10
Total investment securities available for sale	$	248,022	901


	Gross Unrealized Losses		Number of Securities
Investment securities available for sale at December 31, 2023

U.S. Government-sponsored agency securities	$	16,214	14
State and municipal	116,222		691
U.S. Government-sponsored mortgage-backed securities	86,990		150
Corporate obligations	1,128		10
Total investment securities available for sale	$	220,554	865

The unrealized losses in the Corporation’s investment portfolio were the result of changes in interest rates and not credit quality. As a result, the Corporation expects to recover the amortized cost basis over the term of the securities. The Corporation does not intend to sell the investments and it is not more likely than not that the Corporation will be required to sell the investments before recovery of their amortized cost basis, which may be maturity.

Certain investment securities available for sale are reported in the financial statements at an amount less than their historical cost as indicated in the table below.


	March 31, 2024			December 31, 2023
Investments available for sale reported at less than historical cost:
Historical cost	$	1,839,685		$	1,781,108
Fair value	1,591,663			1,560,554
Gross unrealized losses	$	248,022		$	220,554
Percent of the Corporation's investments available for sale	98.2		%	95.9		%

In determining the fair value of the investment securities portfolio, the Corporation utilizes a third party for portfolio accounting services, including market value input, for those securities classified as Level 1 and Level 2 in the fair value hierarchy. The Corporation has obtained an understanding of what inputs are being used by the vendor in pricing the portfolio and how the vendor classified these securities based upon these inputs. From these discussions, the Corporation’s management is comfortable that the classifications are proper. The Corporation has gained trust in the data for two reasons: (a) independent spot testing of the data is conducted by the Corporation through obtaining market quotes from various brokers on a periodic basis; and (b) actual gains or losses resulting from the sale of certain securities has proven the data to be accurate over time. Fair value of securities classified as Level 3 in the valuation hierarchy was determined using a discounted cash flow model that incorporated market estimates of interest rates and volatility in markets that have not been active.

The amortized cost and fair value of investment securities available for sale and held to maturity at March 31, 2024 and December 31, 2023, by contractual maturity are shown below. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity are shown separately.


	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Maturity Distribution at March 31, 2024
Due in one year or less	$	1,865	$	1,855	$	12,971	$	12,831
Due after one through five years	24,392		22,654		112,676		105,283
Due after five through ten years	141,962		131,832		137,043		125,783
Due after ten years	1,134,476		991,828		1,206,968		988,923
	1,302,695		1,148,169		1,469,658		1,232,820
U.S. Government-sponsored mortgage-backed securities	565,177		472,044		693,948		587,631

Total investment securities	$	1,867,872	$	1,620,213	$	2,163,606	$	1,820,451


	Available for Sale				Held to Maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Maturity Distribution at December 31, 2023
Due in one year or less	$	1,390	$	1,382	$	3,041	$	3,043
Due after one through five years	24,899		23,372		118,592		111,723
Due after five through ten years	127,948		120,385		135,805		126,461
Due after ten years	1,151,260		1,027,158		1,217,265		1,018,801
	1,305,497		1,172,297		1,474,703		1,260,028
U.S. Government-sponsored mortgage-backed securities	541,343		454,815		709,794		610,346

Total investment securities	$	1,846,840	$	1,627,112	$	2,184,497	$	1,870,374

Securities with a carrying value of approximately $1.7 billion and $1.8 billion were pledged at March 31, 2024 and December 31, 2023, respectively, to secure certain deposits and securities sold under repurchase agreements, and for other purposes as permitted or required by law.

The book value of securities pledged and available under agreements to repurchase amounted to $152.0 million at March 31, 2024 and $181.4 million at December 31, 2023.

Gross gains and losses on the sales and redemptions of investment securities available for sale for the three months ended March 31, 2024 and 2023 are shown below.


	Three Months Ended March 31,
		2024		2023
Sales and redemptions of investment securities available for sale:
Gross gains		$	—	$	12
Gross losses		(2)		(1,583)

Net gains (losses) on sales and redemptions of investment securities available for sale		$	(2)	$	(1,571)