| Investments by contractual maturity date |
The tables below provide detail regarding the amortized cost and fair value of available-for-sale and held-to-maturity investment securities. | | | | | | | | | | | | | | | | | | | | September 30, 2019 | Amortized Cost | | Gross Unrealized | | Fair Value | | Yield | Gains | | Losses | | | (In thousands) | Available-for-sale securities | | | | | | | | | | U.S. government and agency securities due | | | | | | | | | | 5 to 10 years | $ | 65,287 |
| | $ | 39 |
| | $ | (629 | ) | | $ | 64,697 |
| | 2.43 | % | Over 10 years | 207,067 |
| | 1 |
| | (987 | ) | | 206,081 |
| | 3.02 |
| Corporate debt securities due | | | | | | | | | | Within 1 year | 43,903 |
| | 411 |
| | — |
| | 44,314 |
| | 3.65 |
| 1 to 5 years | 70,000 |
| | 689 |
| | (50 | ) | | 70,639 |
| | 3.29 |
| 5 to 10 years | 92,931 |
| | 1,879 |
| | — |
| | 94,810 |
| | 3.27 |
| Municipal bonds due | | | | | | | | | | 1 to 5 years | 1,430 |
| | 14 |
| | — |
| | 1,444 |
| | 1.94 |
| Over 10 years | 20,303 |
| | 895 |
| | — |
| | 21,198 |
| | 6.45 |
| Mortgage-backed securities | | | | | | | | | | Agency pass-through certificates | 957,150 |
| | 26,533 |
| | (1,124 | ) | | 982,559 |
| | 3.29 |
| | 1,458,071 |
| | 30,461 |
| | (2,790 | ) | | 1,485,742 |
| | 3.27 |
| Held-to-maturity securities | | | | | | | | | | Mortgage-backed securities | | | | | | | | | | Agency pass-through certificates | 1,428,480 |
| | 19,945 |
| | (337 | ) | | 1,448,088 |
| | 3.15 |
| Commercial MBS | 15,000 |
| | 7 |
| | — |
| | 15,007 |
| | 2.89 |
| | 1,443,480 |
| | 19,952 |
| | (337 | ) | | 1,463,095 |
| | 3.15 |
| | $ | 2,901,551 |
| | $ | 50,413 |
| | $ | (3,127 | ) | | $ | 2,948,837 |
| | 3.21 | % |
| | | | | | | | | | | | | | | | | | | | September 30, 2018 | Amortized Cost | | Gross Unrealized | | Fair Value | | Yield | Gains | | Losses | | | (In thousands) | Available-for-sale securities | | | | | | | | | | U.S. government and agency securities due | | | | | | | | | | 5 to 10 years | $ | 60,872 |
| | $ | — |
| | $ | (1,473 | ) | | $ | 59,399 |
| | 2.55 | % | Over 10 years | 148,099 |
| | 109 |
| | (314 | ) | | 147,894 |
| | 3.05 |
| Equity securities | | | | | | | | | | 1 to 5 years | 500 |
| | — |
| | (12 | ) | | 488 |
| | 1.80 |
| Corporate debt securities due | | | | | | | | | | 1 to 5 years | 113,762 |
| | 1,875 |
| | (13 | ) | | 115,624 |
| | 3.59 |
| 5 to 10 years | 69,965 |
| | 35 |
| | (929 | ) | | 69,071 |
| | 3.23 |
| Municipal bonds due | | | | | | | | | | 1 to 5 years | 1,398 |
| | — |
| | (24 | ) | | 1,374 |
| | 2.05 |
| Over 10 years | 20,323 |
| | 1,281 |
| | — |
| | 21,604 |
| | 6.45 |
| Mortgage-backed securities | | | | | | | | | | Agency pass-through certificates | 908,092 |
| | 1,383 |
| | (13,434 | ) | | 896,041 |
| | 3.29 |
| Commercial MBS | 3,460 |
| | 2 |
| | — |
| | 3,462 |
| | 4.36 |
| | 1,326,471 |
| | 4,685 |
| | (16,199 | ) | | 1,314,957 |
| | 3.30 |
| Held-to-maturity securities | | | | | | | | | | Mortgage-backed securities | | | | | | | | | | Agency pass-through certificates | 1,610,420 |
| | 305 |
| | (76,983 | ) | | 1,533,742 |
| | 3.16 |
| Commercial MBS | 15,000 |
| | 28 |
| | — |
| | 15,028 |
| | 3.03 |
| | 1,625,420 |
| | 333 |
| | (76,983 | ) | | 1,548,770 |
| | 3.16 |
| | $ | 2,951,891 |
| | $ | 5,018 |
| | $ | (93,182 | ) | | $ | 2,863,727 |
| | 3.22 | % |
|
| Schedule of unrealized losses and fair value of securities |
The following table shows the gross unrealized losses and fair value of securities at September 30, 2019, and September 30, 2018, by length of time that individual securities in each category have been in a continuous loss position. Management believes that the declines in fair value of these investments are not an other-than-temporary impairment as these losses are due to a change in interest rates rather than any credit deterioration. The impairment is also deemed to be temporary because: 1) the Company does not intend to sell the security, and 2) it is not more likely than not that it will be required to sell the security before recovery of the entire amortized cost basis of the security. | | | | | | | | | | | | | | | | | | | | | September 30, 2019 | | Less than 12 months | 12 months or more | Total | | Unrealized Gross Losses | Fair Value | Unrealized Gross Losses | Fair Value | Unrealized Gross Losses | Fair Value | | (In thousands) | Corporate debt securities | $ | — |
| $ | — |
| $ | (50 | ) | $ | 24,950 |
| $ | (50 | ) | $ | 24,950 |
| U.S. government and agency securities | (656 | ) | 152,715 |
| (960 | ) | 77,391 |
| (1,616 | ) | 230,106 |
| Mortgage-backed securities | (148 | ) | 87,895 |
| (1,313 | ) | 270,802 |
| (1,461 | ) | 358,697 |
| | $ | (804 | ) | $ | 240,610 |
| $ | (2,323 | ) | $ | 373,143 |
| $ | (3,127 | ) | $ | 613,753 |
|
| | | | | | | | | | | | | | | | | | | | | September 30, 2018 | | Less than 12 months | 12 months or more | Total | | Unrealized Gross Losses | Fair Value | Unrealized Gross Losses | Fair Value | Unrealized Gross Losses | Fair Value | | (In thousands) | Corporate debt securities | $ | (929 | ) | $ | 49,072 |
| $ | (14 | ) | $ | 24,988 |
| $ | (943 | ) | $ | 74,060 |
| Municipal bonds | (24 | ) | 1,374 |
| — |
| — |
| (24 | ) | 1,374 |
| U.S. government and agency securities | (141 | ) | 37,565 |
| (1,645 | ) | 76,499 |
| (1,786 | ) | 114,064 |
| Equity securities | (12 | ) | 488 |
| — |
| — |
| (12 | ) | 488 |
| Mortgage-backed securities | (28,748 | ) | 1,035,754 |
| (61,669 | ) | 1,183,017 |
| (90,417 | ) | 2,218,771 |
| | $ | (29,854 | ) | $ | 1,124,253 |
| $ | (63,328 | ) | $ | 1,284,504 |
| $ | (93,182 | ) | $ | 2,408,757 |
|
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