| Investment Securities |
Investment Securities The following table presents the amortized cost and estimated fair values of investment securities: | | | | | | | | | | | | | | | | | | | | | | | | | June 30, 2026 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | | Available for Sale | (dollars in thousands) | | | | | | | | | | | | | | | | | | State and municipal securities | $ | 931,962 | | | $ | 224 | | | $ | (116,231) | | | $ | 815,955 | | | Corporate debt securities | 210,070 | | | 1,596 | | | (4,091) | | | 207,575 | | | Collateralized mortgage obligations | 1,192,896 | | | 3,062 | | | (11,639) | | | 1,184,319 | | | Residential mortgage-backed securities | 786,030 | | | 3,351 | | | (23,853) | | | 765,528 | | | Commercial mortgage-backed securities | 679,928 | | | — | | | (92,255) | | | 587,673 | | | | | | | | | | | Total | $ | 3,800,886 | | | $ | 8,233 | | | $ | (248,069) | | | $ | 3,561,050 | | | | | | | | | | | Held to Maturity | | | | | | | | | Residential mortgage-backed securities | $ | 516,680 | | | $ | 2,936 | | | $ | (44,721) | | | $ | 474,895 | | | Collateralized mortgage obligations | 163,019 | | | — | | | (2,840) | | | 160,179 | | | Commercial mortgage-backed securities | 882,010 | | | — | | | (123,346) | | | 758,664 | | | Total | $ | 1,561,709 | | | $ | 2,936 | | | $ | (170,907) | | | $ | 1,393,738 | |
| | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2025 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | | Available for Sale | (dollars in thousands) | | | | | | | | | | | | | | | | | | State and municipal securities | $ | 951,764 | | | $ | 326 | | | $ | (125,397) | | | $ | 826,693 | | | Corporate debt securities | 219,699 | | | 1,302 | | | (6,080) | | | 214,921 | | | Collateralized mortgage obligations | 1,034,548 | | | 12,758 | | | (7,228) | | | 1,040,078 | | | Residential mortgage-backed securities | 781,966 | | | 5,891 | | | (21,140) | | | 766,717 | | | Commercial mortgage-backed securities | 647,375 | | | 80 | | | (88,005) | | | 559,450 | | | | | | | | | | | Total | $ | 3,635,352 | | | $ | 20,357 | | | $ | (247,850) | | | $ | 3,407,859 | | | | | | | | | | | | | | | | | | | | | | | | | | | Held to Maturity | | | | | | | | | Residential mortgage-backed securities | $ | 573,636 | | | $ | 4,978 | | | $ | (44,093) | | | $ | 534,521 | | | Commercial mortgage-backed securities | 852,249 | | | — | | | (119,192) | | | 733,057 | | | Total | $ | 1,425,885 | | | $ | 4,978 | | | $ | (163,285) | | | $ | 1,267,578 | |
Investment securities carried at $322.8 million and $373.3 million at June 30, 2026 and December 31, 2025, 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, 2026, 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. | | | | | | | | | | | | | | | | | | | | | | | | | | | | | June 30, 2026 | | | 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 | | $ | 6,530 | | | $ | 6,486 | | | $ | — | | | $ | — | | | Due from one year to five years | | 88,012 | | | 87,206 | | | — | | | — | | | Due from five years to ten years | | 221,810 | | | 219,079 | | | — | | | — | | | Due after ten years | | 825,680 | | | 710,759 | | | — | | | — | | | | 1,142,032 | | | 1,023,530 | | | — | | | — | | Residential mortgage-backed securities(1) | | 786,030 | | | 765,528 | | | 516,680 | | | 474,895 | | Commercial mortgage-backed securities(1) | | 679,928 | | | 587,673 | | | 882,010 | | | 758,664 | | Collateralized mortgage obligations(1) | | 1,192,896 | | | 1,184,319 | | | 163,019 | | | 160,179 | | | Total | | $ | 3,800,886 | | | $ | 3,561,050 | | | $ | 1,561,709 | | | $ | 1,393,738 | |
(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) | | June 30, 2026 | $ | — | | | $ | — | | | | | $ | — | | | June 30, 2025 | — | | | — | | | | | — | | | | | | | | | | | Six months ended | | | | | | | | | June 30, 2026 | $ | — | | | $ | — | | | | | $ | — | | | June 30, 2025 | 663 | | | (665) | | | | | (2) | |
The following tables present the gross unrealized losses and estimated fair values of investments aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | June 30, 2026 | | 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 | 28 | | | $ | 60,146 | | | $ | (597) | | | 252 | | | $ | 729,402 | | | $ | (115,634) | | | $ | 789,548 | | | $ | (116,231) | | | Corporate debt securities | 9 | | | 47,846 | | | (301) | | | 16 | | | 106,943 | | | (3,790) | | | 154,789 | | | (4,091) | | | Collateralized mortgage obligations | 25 | | | 495,539 | | | (3,998) | | | 68 | | | 67,346 | | | (7,641) | | | 562,885 | | | (11,639) | | | Residential mortgage-backed securities | 25 | | | 252,623 | | | (1,755) | | | 71 | | | 184,811 | | | (22,098) | | | 437,434 | | | (23,853) | | | Commercial mortgage-backed securities | 11 | | | 140,048 | | | (2,137) | | | 128 | | | 447,625 | | | (90,118) | | | 587,673 | | | (92,255) | | | Total available for sale | 98 | | | $ | 996,202 | | | $ | (8,788) | | | 535 | | | $ | 1,536,127 | | | $ | (239,281) | | | $ | 2,532,329 | | | $ | (248,069) | | | | | | | | | | | | | | | | | | | Held to Maturity | | | | | | | | | | | | | | | | | Residential mortgage-backed securities | 4 | | | $ | 34,560 | | | $ | (290) | | | 118 | | | $ | 240,575 | | | $ | (44,431) | | | $ | 275,135 | | | $ | (44,721) | | | Collateralized mortgage obligations | 4 | | | 160,179 | | | (2,840) | | | — | | | — | | | — | | | 160,179 | | | (2,840) | | | Commercial mortgage-backed securities | 1 | | | 33,962 | | | (890) | | | 60 | | | 724,702 | | | (122,456) | | | 758,664 | | | (123,346) | | | Total held to maturity | 9 | | | $ | 228,701 | | | $ | (4,020) | | | 178 | | | $ | 965,277 | | | $ | (166,887) | | | $ | 1,193,978 | | | $ | (170,907) | |
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | December 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 | 3 | | | $ | 10,532 | | | $ | (127) | | | 277 | | | $ | 776,597 | | | $ | (125,270) | | | $ | 787,129 | | | $ | (125,397) | | | Corporate debt securities | 5 | | | 22,911 | | | (329) | | | 21 | | | 145,563 | | | (5,751) | | | 168,474 | | | (6,080) | | | Collateralized mortgage obligations | 1 | | | 19,806 | | | (128) | | | 72 | | | 74,446 | | | (7,100) | | | 94,252 | | | (7,228) | | | Residential mortgage-backed securities | 3 | | | 34,766 | | | (97) | | | 75 | | | 240,422 | | | (21,043) | | | 275,188 | | | (21,140) | | | Commercial mortgage-backed securities | 4 | | | 51,600 | | | (155) | | | 131 | | | 493,235 | | | (87,850) | | | 544,835 | | | (88,005) | | | Total available for sale | 16 | | | $ | 139,615 | | | $ | (836) | | | 576 | | | $ | 1,730,263 | | | $ | (247,014) | | | $ | 1,869,878 | | | $ | (247,850) | | | | | | | | | | | | | | | | | | | Held to Maturity | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Residential mortgage-backed securities | — | | | $ | — | | | $ | — | | | 120 | | | $ | 275,497 | | | $ | (44,093) | | | $ | 275,497 | | | $ | (44,093) | | | Commercial mortgage-backed securities | — | | | — | | | — | | | 60 | | | 733,057 | | | (119,192) | | | 733,057 | | | (119,192) | | | Total held to maturity | — | | | $ | — | | | $ | — | | | 180 | | | $ | 1,008,554 | | | $ | (163,285) | | | $ | 1,008,554 | | | $ | (163,285) | |
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 GSEs. Therefore, the Corporation did not record an ACL for these securities as of June 30, 2026 and December 31, 2025. 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 June 30, 2026 and December 31, 2025. 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 June 30, 2026 and December 31, 2025. 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, 2026 and December 31, 2025. 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.
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