Investment Securities

6 Months Ended

Jun. 30, 2024

Investments, Debt and Equity Securities [Abstract]

3. Investment Securities

The following table summarizes the amortized cost and fair value of securities that are classified as available-for-sale and held-to-maturity:


	June 30, 2024
	Available-for-Sale
	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized (Losses)		Estimated Fair Value
	(In thousands)
U.S. government-sponsored enterprises	$	334,736	$	—	$	334,736	$	1,626	$	(16,869)	$	319,493
U.S. government-sponsored mortgage-backed securities	1,621,192		—		1,621,192		547		(201,264)		1,420,475
Private mortgage-backed securities	188,551		—		188,551		—		(15,418)		173,133
Non-government-sponsored asset backed securities	358,968		—		358,968		700		(5,869)		353,799
State and political subdivisions	972,688		—		972,688		583		(83,006)		890,265
Other securities	215,733		(2,525)		213,208		466		(26,300)		187,374
Total	$	3,691,868	$	(2,525)	$	3,689,343	$	3,922	$	(348,726)	$	3,344,539


	June 30, 2024
	Held-to-Maturity
	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized (Losses)		Estimated Fair Value
	(In thousands)
U.S. government-sponsored enterprises	$	43,421	$	—	$	43,421	$	—	$	(3,146)	$	40,275
U.S. government-sponsored mortgage-backed securities	127,464		—		127,464		47		(6,084)		121,427
State and political subdivisions	1,109,973		(2,005)		1,107,968		80		(110,590)		997,458

Total	$	1,280,858	$	(2,005)	$	1,278,853	$	127	$	(119,820)	$	1,159,160


	December 31, 2023
	Available-for-Sale
	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized (Losses)		Estimated Fair Value
	(In thousands)
U.S. government-sponsored enterprises	$	361,494	$	—	$	361,494	$	2,247	$	(17,093)	$	346,648
U.S. government-sponsored mortgage-backed securities	1,711,668		—		1,711,668		310		(191,557)		1,520,421
Private mortgage-backed securities	191,522		—		191,522		—		(16,117)		175,405
Non-government-sponsored asset backed securities	370,203				370,203		821		(7,551)		363,473
State and political subdivisions	990,318		—		990,318		1,938		(75,931)		916,325
Other securities	215,722		(2,525)		213,197		402		(28,030)		185,569
Total	$	3,840,927	$	(2,525)	$	3,838,402	$	5,718	$	(336,279)	$	3,507,841


	December 31, 2023
	Held-to-Maturity
	Amortized Cost		Allowance for Credit Losses		Net Carrying Amount		Gross Unrealized Gains		Gross Unrealized (Losses)		Estimated Fair Value
	(In thousands)
U.S. government-sponsored enterprises	$	43,285	$	—	$	43,285	$	—	$	(2,607)	$	40,678
U.S. government-sponsored mortgage-backed securities	130,278		—		130,278		106		(4,362)		126,022
State and political subdivisions	1,110,424		(2,005)		1,108,419		456		(105,094)		1,003,781

Total	$	1,283,987	$	(2,005)	$	1,281,982	$	562	$	(112,063)	$	1,170,481

Assets, principally investment securities, having a carrying value of approximately $3.03 billion and $3.57 billion at June 30, 2024 and December 31, 2023, respectively, were pledged to secure public deposits, as collateral for repurchase agreements, and for other purposes required or permitted by law. Investment securities pledged as collateral for repurchase agreements totaled approximately $138.0 million and $142.1 million at June 30, 2024 and December 31, 2023, respectively.

The amortized cost and estimated fair value of securities classified as available-for-sale and held-to-maturity at June 30, 2024, by contractual maturity, are shown below. Expected maturities could 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 date are shown separately.


	Available-for-Sale				Held-to-Maturity
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(In thousands)
Due in one year or less	$	21,983	$	21,854	$	—	$	—
Due after one year through five years	242,321		226,640		32,900		30,933
Due after five years through ten years	406,876		364,876		319,351		289,436
Due after ten years	851,977		783,762		801,143		717,364
U.S. government-sponsored mortgage-backed securities	1,621,192		1,420,475		127,464		121,427
Private mortgage-backed securities	188,551		173,133		—		—
Non-government-sponsored asset backed securities	358,968		353,799		—		—
Total	$	3,691,868	$	3,344,539	$	1,280,858	$	1,159,160

During the three and six months ended June 30, 2024 and 2023, no available-for-sale securities were sold.

The following table shows gross unrealized losses and estimated fair value of investment securities classified as available-for-sale and held-to-maturity, aggregated by investment category and length of time that individual investment securities have been in a continuous loss position as of June 30, 2024 and December 31, 2023.


	June 30, 2024
	Less Than 12 Months				12 Months or More				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In thousands)
Available-for-sale:
U.S. government-sponsored enterprises	$	15,810	$	(253)	$	173,941	$	(16,616)	$	189,751	$	(16,869)
U.S. government-sponsored mortgage-backed securities	4,890		(159)		1,363,467		(201,105)		1,368,357		(201,264)
Private mortgage-backed securities	—		—		173,133		(15,418)		173,133		(15,418)
Non-government-sponsored asset backed securities	—		—		145,821		(5,869)		145,821		(5,869)
State and political subdivisions	43,265		(1,163)		776,764		(81,843)		820,029		(83,006)
Other securities	6,733		(1,309)		167,350		(24,991)		174,083		(26,300)
Total	$	70,698	$	(2,884)	$	2,800,476	$	(345,842)	$	2,871,174	$	(348,726)
Held-to-maturity:
U.S. government-sponsored enterprises	$	—	$	—	$	40,275	$	(3,146)	$	40,275	$	(3,146)
U.S. government-sponsored mortgage-backed securities	6,202		(188)		10,954		(5,896)		17,156		(6,084)


State and political subdivisions	30,525		(799)		963,658		(109,791)		994,183		(110,590)
Total	$	36,727	$	(987)	$	1,014,887	$	(118,833)	$	1,051,614	$	(119,820)


	December 31, 2023
	Less Than 12 Months				12 Months or More				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
	(In thousands)
Available-for-sale:
U.S. government-sponsored enterprises	$	2,742	$	(2)	$	180,569	$	(17,091)	$	183,311	$	(17,093)
U.S. government-sponsored mortgage-backed securities	102,831		(2,166)		1,392,318		(189,391)		1,495,149		(191,557)
Private mortgage-backed securities	9,298		(226)		166,107		(15,891)		175,405		(16,117)
Non-government-sponsored asset backed securities	—		—		213,838		(7,551)		213,838		(7,551)
State and political subdivisions	28,596		(400)		769,860		(75,531)		798,456		(75,931)
Other securities	—		—		164,430		(28,030)		164,430		(28,030)
Total	$	143,467	$	(2,794)	$	2,887,122	$	(333,485)	$	3,030,589	$	(336,279)
Held-to-maturity:
U.S. government-sponsored enterprises	$	—	$	—	$	40,677	$	(2,607)	$	40,677	$	(2,607)
U.S. government-sponsored mortgage-backed securities	48,498		(861)		65,573		(3,501)		114,071		(4,362)


State and political subdivisions	21,493		(297)		956,578		(104,797)		978,071		(105,094)
Total	$	69,991	$	(1,158)	$	1,062,828	$	(110,905)	$	1,132,819	$	(112,063)

Debt securities available-for-sale ("AFS") are reported at fair value with unrealized holding gains and losses reported as a separate component of stockholders’ equity and other comprehensive income (loss), net of taxes. Securities that are held as available-for-sale are used as a part of our asset/liability management strategy. Securities that may be sold in response to interest rate changes, changes in prepayment risk, the need to increase regulatory capital, and other similar factors are classified as available-for-sale. The Company evaluates all securities quarterly to determine if any securities in a loss position require a provision for credit losses. The Company first assesses whether it intends to sell or is more likely than not that the Company 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 income. For securities that do not meet these criteria, the Company evaluates whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, the Company considers the extent to which fair value is less than amortized cost, and 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. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. The Company has made the election to exclude accrued interest receivable on AFS securities from the estimate of credit losses and report accrued interest separately on the consolidated balance sheets. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectability of a security is confirmed or when either of the criteria regarding intent or requirement to sell is met.

Debt securities held-to-maturity ("HTM"), which include any security for which we have the positive intent and ability to hold until maturity, are reported at historical cost adjusted for amortization of premiums and accretion of discounts. Premiums and discounts are amortized/accreted to the call date to interest income using the constant effective yield method over the estimated life of the security. The Company evaluates all securities quarterly to determine if any securities in a loss position require a provision for credit losses. The Company measures expected credit losses on HTM securities on a collective basis by major security type, with each type sharing similar risk characteristics. The estimate of expected credit losses considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. The Company has made the election to exclude accrued interest receivable on HTM securities from the estimate of credit losses and report accrued interest separately on the consolidated balance sheets. Changes in the allowance for credit losses are recorded as provision for (or reversal of) credit loss expense. Losses are charged against the allowance when management believes the uncollectability of a security is confirmed.

During the period ended June 30, 2024, the Company determined the $2.5 million allowance for credit losses on the available for sale portfolio and the $2.0 million allowance for credit losses on the held-to-maturity portfolio were adequate. Therefore, no additional provision was considered necessary.


Available-for-Sale Investment Securities
	June 30, 2024		December 31, 2023
Allowance for credit losses:	(In thousands)
Beginning balance	$	2,525	$	842
Provision for credit loss	—		1,683
Balance, June 30	$	2,525	$	2,525
Provision for credit loss			—
Balance, December 31, 2023			$	2,525


Held-to-Maturity Investment Securities
	June 30, 2024		December 31, 2023
Allowance for credit losses:	(In thousands)
Beginning balance	$	2,005	$	2,005
Provision for credit loss	—		—
Balance, June 30	$	2,005	$	2,005
Provision for credit loss			—
Balance, December 31, 2023			$	2,005

For the six months ended June 30, 2024, the Company had available-for-sale investment securities with approximately $348.7 million in unrealized losses, of which $345.8 million had been in continuous loss positions for more than twelve months. With the exception of the subordinated debt investment securities which were downgraded during 2023 resulting in the allowance, the Company’s assessments indicated the cause of the market depreciation was primarily due to the change in interest rates and not the issuer’s financial condition or downgrades by rating agencies. In addition, approximately 29.6% of the principal balance from the Company’s investment portfolio will mature or are expected to pay down within five years or less. As a result, the Company has the ability and intent to hold such securities until maturity.

As of June 30, 2024, the Company's available-for-sale securities portfolio consisted of 1,559 investment securities, 1,317 of which were in an unrealized loss position. As noted in the table above, the total amount of the unrealized loss was $348.7 million. The U.S. government-sponsored enterprises portfolio contained unrealized losses of $16.9 million on 56 securities. The U.S. government-sponsored mortgage-backed securities portfolio contained $201.3 million of unrealized losses on 656 securities, and the private mortgage-backed securities portfolio contained $15.4 million of unrealized losses on 32 securities. The non-government-sponsored asset backed securities portfolio contained $5.9 million of unrealized losses on 27 securities. The state and political subdivisions portfolio contained $83.0 million of unrealized losses on 483 securities. In addition, the other securities portfolio contained $26.3 million of unrealized losses on 63 securities. With the exception of the investments for which an allowance for credit losses has been established, the unrealized losses on the Company's investments were primarily a result of interest rate changes, and the Company expects to recover the amortized cost basis over the term of the securities. The Company has determined that, as of June 30, 2024, an additional provision for credit losses is not necessary because the decline in market value was attributable to changes in interest rates and not credit quality, and because the Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis, which may be maturity.

As of June 30, 2024, the Company's held-to-maturity securities portfolio consisted of 508 investment securities, 501 of which were in an unrealized loss position. As noted in the table above, the total amount of the unrealized loss was $119.8 million. The U.S. government-sponsored enterprises portfolio contained unrealized losses of $3.1 million on 5 securities. The U.S. government-sponsored mortgage-backed securities portfolio contained unrealized losses of $6.1 million on 19 securities. The state and political subdivisions portfolio contained $110.6 million of unrealized losses on 477 securities. The unrealized losses on the Company's investments were a result of interest rate changes. The Company expects to recover the amortized cost basis over the term of the securities. Because the decline in market value was attributable to changes in interest rates and not credit quality, the Company has determined that an additional provision for credit losses was not necessary as of June 30, 2024.

The following table summarizes bond ratings for the Company’s held-to-maturity portfolio, based upon amortized cost, issued by state and political subdivisions and other securities as of June 30, 2024:


	State and political subdivisions		U.S. government-sponsored enterprises		U.S. government-sponsored mortgage-backed securities		Total
	(In thousands)
Aaa/AAA	$	234,801	$	43,421	$	—	$	278,222
Aa/AA	850,072		—		—		850,072
A	23,191		—		—		23,191

Not rated	1,909		—		—		1,909
Agency Backed	—		—		127,464		127,464
Total	$	1,109,973	$	43,421	$	127,464	$	1,280,858

Income earned on securities for the three months ended June 30, 2024 and 2023, is as follows:


	Three Months Ended June 30,				For the Six Months Ended June 30,
	2024		2023		2024		2023
	(In thousands)
Taxable
Available-for-sale	$	25,127	$	27,254	$	50,889	$	55,052
Held-to-maturity	7,460		7,497		14,927		14,987
Non-taxable
Available-for-sale	4,664		4,798		9,359		9,623
Held-to-maturity	3,105		3,134		6,213		6,272
Total	$	40,356	$	42,683	$	81,388	$	85,934