v3.26.3
INVESTMENT SECURITIES (Tables)
9 Months Ended
Sep. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Summary of Amortized Cost, Gross Unrealized Gains and Losses and Approximate Fair Value of Investment Securities
The following tables summarize the amortized cost, gross unrealized gains and losses and approximate fair value of investment securities available for sale as of September 30, 2026 and December 31, 2025.

Amortized
Cost
Gross Unrealized
Gains
Gross Unrealized
Losses
Fair
Value
Available for sale at September 30, 2026
U.S. Government-sponsored agency securities$81,543 $— $(14,347)$67,196 
State and municipal982,812 — (192,870)789,942 
U.S. Government-sponsored mortgage-backed securities469,402 7 (83,370)386,039 
Foreign investment1,500 — (9)1,491 
Corporate obligations7,017 11 (156)6,872 
Total available for sale$1,542,274 $18 $(290,752)$1,251,540 

Amortized
Cost
Gross Unrealized
Gains
Gross Unrealized
Losses
Fair
Value
Available for sale at December 31, 2025
U.S. Government-sponsored agency securities$87,936 $— $(11,837)$76,099 
State and municipal993,911 225 (91,842)902,294 
U.S. Government-sponsored mortgage-backed securities482,702 1,600 (64,792)419,510 
Foreign investment1,500 — — 1,500 
Corporate obligations7,974 1 (276)7,699 
Total available for sale$1,574,023 $1,826 $(168,747)$1,407,102 

The following tables summarize the amortized cost, gross unrealized gains and losses, approximate fair value and allowance for credit losses on investment securities held to maturity as of September 30, 2026 and December 31, 2025.

Amortized
Cost
Allowance for Credit LossesNet Carrying AmountGross Unrealized
Gains
Gross Unrealized
Losses
Fair
Value
Held to maturity at September 30, 2026
U.S. Government-sponsored agency securities$308,998 $— $308,998 $— $(52,277)$256,721 
State and municipal1,043,391 (245)1,043,146 2 (237,783)805,610 
U.S. Government-sponsored mortgage-backed securities520,807 — 520,807 — (87,661)433,146 
Total held to maturity$1,873,196 $(245)$1,872,951 $2 $(377,721)$1,495,477 

Amortized
Cost
Allowance for Credit LossesNet Carrying AmountGross Unrealized
Gains
Gross Unrealized
Losses
Fair
Value
Held to maturity at December 31, 2025
U.S. Government-sponsored agency securities$324,643 $— $324,643 $— $(46,693)$277,950 
State and municipal1,069,653 (245)1,069,408 868 (137,706)932,815 
U.S. Government-sponsored mortgage-backed securities577,488 — 577,488 — (69,966)507,522 
Total held to maturity$1,971,784 $(245)$1,971,539 $868 $(254,365)$1,718,287 
Summary of Amortized Cost of Investment Securities Held to Maturity Aggregated by Credit Quality Indicator
On a quarterly basis, the Corporation monitors the credit quality of investment securities held to maturity through the use of issuer financial information and credit ratings. The following tables summarize the amortized cost of investment securities held to maturity at September 30, 2026 and December 31, 2025, aggregated by credit quality indicator.
September 30, 2026
U.S. Government-sponsored agency securities (1)
State and municipal
U.S. Government-sponsored mortgage-backed securities (1)
Total
Credit Rating:
Aaa$308,998 $73,549 $520,807 $903,354 
Aa1— 216,863 — 216,863 
Aa2— 148,671 — 148,671 
Aa3— 187,732 — 187,732 
A1— 59,622 — 59,622 
A2— 10,192 — 10,192 
A3— 10,156 — 10,156 
Non-rated— 336,606 — 336,606 
Total$308,998 $1,043,391 $520,807 $1,873,196 
(1) U.S. Government-sponsored agency securities and U.S. Government-sponsored mortgage-backed securities are included within the Aaa credit rating category due to their explicit or implicit government guarantees, which provide a high level of assurance regarding the timely collection of principal and interest payments.

December 31, 2025
U.S. Government-sponsored agency securities (1)
State and municipal
U.S. Government-sponsored mortgage-backed securities (1)
Total
Credit Rating:
Aaa$324,643 $75,598 $577,488 $977,729 
Aa1— 200,189 — 200,189 
Aa2— 172,127 — 172,127 
Aa3— 192,682 — 192,682 
A1— 59,631 — 59,631 
A2— 13,664 — 13,664 
A3— 6,670 — 6,670 
Non-rated— 349,092 — 349,092 
Total$324,643 $1,069,653 $577,488 $1,971,784 
(1) U.S. Government-sponsored agency securities and U.S. Government-sponsored mortgage-backed securities are included within the Aaa credit rating category due to their explicit or implicit government guarantees, which provide a high level of assurance regarding the timely collection of principal and interest payments.
Summary of Investment Securities in a Continuous Unrealized Loss Position
The following tables summarize, as of September 30, 2026 and December 31, 2025, 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 Months12 Months or LongerTotal
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Investment securities available for sale at September 30, 2026
U.S. Government-sponsored agency securities$30 $(1)$67,166 $(14,346)$67,196 $(14,347)
State and municipal96,818 (10,760)693,124 (182,110)789,942 (192,870)
U.S. Government-sponsored mortgage-backed securities107,153 (4,070)276,098 (79,300)383,251 (83,370)
Foreign investment1,491 (9)— — 1,491 (9)
Corporate obligations982 (17)5,319 (139)6,301 (156)
Total investment securities available for sale$206,474 $(14,857)$1,041,707 $(275,895)$1,248,181 $(290,752)
Less than 12 Months12 Months or LongerTotal
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Fair
Value
Gross
Unrealized
Losses
Investment securities available for sale at December 31, 2025
U.S. Government-sponsored agency securities$— $— $76,099 $(11,837)$76,099 $(11,837)
State and municipal5,468 (11)861,410 (91,830)866,878 (91,841)
U.S. Government-sponsored mortgage-backed securities4,885 (10)313,353 (64,783)318,238 (64,793)
Corporate obligations— — 6,676 (276)6,676 (276)
Total investment securities available for sale$10,353 $(21)$1,257,538 $(168,726)$1,267,891 $(168,747)

The following tables summarize 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 September 30, 2026
U.S. Government-sponsored agency securities$(14,347)13
State and municipal(192,870)617
U.S. Government-sponsored mortgage-backed securities(83,370)135
Foreign investment(9)1
Corporate obligations(156)4
Total investment securities available for sale$(290,752)770 

Gross
Unrealized
Losses
Number of Securities
Investment securities available for sale at December 31, 2025
U.S. Government-sponsored agency securities$(11,837)12
State and municipal(91,841)587
U.S. Government-sponsored mortgage-backed securities(64,793)89
Corporate obligations(276)5
Total investment securities available for sale$(168,747)693 
Summary of Investments in Debt and Equity Securities Reported in the Financial Statements at an Amount Less Than Their Historical Cost
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.
September 30, 2026December 31, 2025
Investment securities available for sale reported at less than historical cost:
Historical cost$1,538,933 $1,436,638 
Fair value1,248,181 1,267,891 
Gross unrealized losses$(290,752)$(168,747)
Percentage of the Corporation's investment securities available for sale in an unrealized loss position99.7 %90.1 %
Summary of Amortized Cost and Fair Value of Available for Sale Securities and Held to Maturity Securities by Contractual Maturity
The amortized cost and fair value of investment securities available for sale and held to maturity at September 30, 2026 and December 31, 2025, 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 SaleHeld to Maturity
Amortized CostFair ValueAmortized CostFair Value
Maturity Distribution at September 30, 2026
Due in one year or less$748 $741 $35,613 $34,981 
Due after one through five years23,922 22,675 120,348 112,583 
Due after five through ten years329,137 277,575 265,174 216,934 
Due after ten years719,065 564,510 931,254 697,833 
1,072,872 865,501 1,352,389 1,062,331 
U.S. Government-sponsored mortgage-backed securities469,402 386,039 520,807 433,146 
Total investment securities$1,542,274 $1,251,540 $1,873,196 $1,495,477 

Available for SaleHeld to Maturity
Amortized CostFair ValueAmortized CostFair Value
Maturity Distribution at December 31, 2025
Due in one year or less$— $— $7,014 $7,024 
Due after one through five years16,877 16,577 118,912 115,973 
Due after five through ten years241,803 227,493 228,224 210,125 
Due after ten years832,641 743,522 1,040,146 877,643 
1,091,321 987,592 1,394,296 1,210,765 
U.S. Government-sponsored mortgage-backed securities482,702 419,510 577,488 507,522 
Total investment securities$1,574,023 $1,407,102 $1,971,784 $1,718,287 
Summary of Gross Gains and Losses on Sales and Redemptions of Available for Sale Securities Gross gains and losses on the sales of investment securities available for sale for the nine months ended September 30, 2025 is shown below.
Nine Months Ended September 30,
2025
Sales of investment securities available for sale:
Gross gains$— 
Gross losses(8)
Net losses on sales of investment securities available for sale$(8)