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INVESTMENT SECURITIES - Investments by Contractual Maturity Date (Details) - USD ($) $ in Thousands | Sep. 30, 2025 | Sep. 30, 2024
--- | --- | ---
Amortized Cost, Available-for-sale securities |  |
Amortized cost | $ 3,542,438 | $ 2,616,877
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains | 40,997 | 10,531
Gross unrealized loss | (50,234) | (54,699)
Fair Value, Available-for-sale securities |  |
Available-for-sale securities, at fair value | $ 3,533,201 | $ 2,572,709
Yield, Available-for-sale securities |  |
Yield | 4.17% | 4.87%
Yield, Held-to-maturity securities |  |
Investments | $ 4,188,240 | $ 3,053,849
Gross unrealized gains on investments | 45,070 | 11,444
Gross unrealized losses on investments | (87,370) | (91,538)
Total Financial Assets | $ 4,145,940 | $ 2,973,755
Yield on investments | 4.12% | 4.63%
U.S. government and agency securities due |  |
Amortized Cost, Available-for-sale securities |  |
Within 1 year | $ 1,687 | $ 4,360
1 to 5 years | 545 | 4,640
5 to 10 years | 158,026 | 166,070
Over 10 years | 75,887 | 137,799
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains, within 1 year | 0 | 4
Gross unrealized gains, 1 to 5 years | 0 | 2
Gross unrealized gains, 5 to 10 years | 162 | 1,230
Gross unrealized gains, over 10 years | 163 | 394
Gross unrealized losses, within 1 year | (29) | 0
Gross unrealized losses, 1 to 5 years | 0 | (124)
Gross unrealized losses, 5 to 10 years | (295) | 0
Gross unrealized losses, over 10 years | (227) | (171)
Fair Value, Available-for-sale securities |  |
Within 1 year | 1,658 | 4,364
1 to 5 years | 545 | 4,518
5 to 10 years | 157,893 | 167,300
Over 10 years | $ 75,823 | $ 138,022
Yield, Available-for-sale securities |  |
Within 1 year | 2.05% | 5.58%
1 to 5 years | 5.00% | 2.82%
5 to 10 years | 4.95% | 5.97%
Over 10 years | 5.52% | 6.29%
Asset-backed securities due |  |
Amortized Cost, Available-for-sale securities |  |
Within 1 year | $ 10,492 |
1 to 5 years |  | $ 11,466
5 to 10 years | 3,945 | 9,631
Over 10 years | 491,734 | 520,756
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains, within 1 year | 0 |
Gross unrealized gains, 1 to 5 years |  | 0
Gross unrealized gains, 5 to 10 years | 7 | 0
Gross unrealized gains, over 10 years | 1,702 | 600
Gross unrealized losses, within 1 year | (163) |
Gross unrealized losses, 1 to 5 years |  | (284)
Gross unrealized losses, 5 to 10 years | 0 | (3)
Gross unrealized losses, over 10 years | (1,383) | (2,041)
Fair Value, Available-for-sale securities |  |
Within 1 year | 10,329 |
1 to 5 years |  | 11,182
5 to 10 years | 3,952 | 9,628
Over 10 years | $ 492,053 | $ 519,315
Yield, Available-for-sale securities |  |
Within 1 year | 5.12% |
1 to 5 years |  | 6.04%
5 to 10 years | 5.27% | 6.20%
Over 10 years | 5.36% | 6.15%
Corporate debt securities |  |
Amortized Cost, Available-for-sale securities |  |
Within 1 year |  | $ 45,024
1 to 5 years | $ 32,821 | 99,244
5 to 10 years | 128,015 | 112,029
Over 10 years |  | 50,000
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains, within 1 year |  | 0
Gross unrealized gains, 1 to 5 years | 0 | 977
Gross unrealized gains, 5 to 10 years | 314 | 0
Gross unrealized gains, over 10 years |  | 0
Gross unrealized losses, within 1 year |  | (367)
Gross unrealized losses, 1 to 5 years | (2,047) | 0
Gross unrealized losses, 5 to 10 years | (6,566) | (10,625)
Gross unrealized losses, over 10 years |  | 0
Fair Value, Available-for-sale securities |  |
Within 1 year |  | 44,657
1 to 5 years | 30,774 | 100,221
5 to 10 years | $ 121,763 | 101,404
Over 10 years |  | $ 50,000
Yield, Available-for-sale securities |  |
Within 1 year |  | 4.61%
1 to 5 years | 4.95% | 5.39%
5 to 10 years | 4.37% | 3.87%
Over 10 years |  | 6.85%
Municipal bonds |  |
Amortized Cost, Available-for-sale securities |  |
5 to 10 years | $ 25,659 | $ 5,689
Over 10 years | 9,754 | 29,793
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains, 5 to 10 years | 250 | 0
Gross unrealized gains, over 10 years | 0 | 0
Gross unrealized losses, 5 to 10 years | (179) | (243)
Gross unrealized losses, over 10 years | (226) | (166)
Fair Value, Available-for-sale securities |  |
5 to 10 years | 25,730 | 5,446
Over 10 years | $ 9,528 | $ 29,627
Yield, Available-for-sale securities |  |
5 to 10 years | 5.71% | 3.00%
Over 10 years | 4.57% | 5.85%
Agency pass-through certificates |  |
Amortized Cost, Available-for-sale securities |  |
Without single maturity date | $ 2,603,873 | $ 1,420,376
Gross Unrealized Gains / Losses, Available-for-sale securities |  |
Gross unrealized gains, without single maturity date | 38,399 | 7,324
Gross unrealized losses, without single maturity date | (39,119) | (40,675)
Fair Value, Available-for-sale securities |  |
Without single maturity date | $ 2,603,153 | $ 1,387,025
Yield, Available-for-sale securities |  |
Without single maturity date | 3.83% | 4.09%
Amortized Cost, Held-to-maturity securities |  |
Without single maturity date | $ 645,802 | $ 436,972
Gross Unrealized Gains / Losses, Held-to-maturity securities |  |
Gross unrealized gains, without single maturity date | 4,073 | 913
Gross unrealized losses, without single maturity date | (37,136) | (36,839)
Fair Value, Held-to-maturity securities |  |
Without single maturity date | $ 612,739 | $ 401,046
Yield, Held-to-maturity securities |  |
Without single maturity date | 3.85% | 3.18%

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