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Bank segment - Components of investment securities (Details) $ in Thousands | Jun. 30, 2022 USD ($) issue | Dec. 31, 2021 USD ($) issue
--- | --- | ---
Available-for-sale |  |
Available-for-sale investment securities, at fair value | $ 2,444,267 | $ 2,574,618
Held-to-maturity |  |
Amortized cost | 513,767 | 522,270
Held-to-maturity investment securities | 440,023 |
American Savings Bank (ASB) |  |
Available-for-sale |  |
Amortized cost | 2,773,905 | 2,618,384
Gross unrealized gains | 467 | 7,969
Gross unrealized losses | (330,105) | (51,735)
Available-for-sale investment securities, at fair value | $ 2,444,267 | $ 2,574,618
Gross unrealized losses, less than 12 months, number of issues | issue | 202 | 125
Gross unrealized losses, less than 12 months, fair value | $ 1,553,863 | $ 1,902,850
Gross unrealized losses, less than 12 months, amount | $ (166,155) | $ (38,850)
Gross unrealized losses, 12 months or longer, number of issues | issue | 66 | 18
Gross unrealized losses, 12 months or longer, fair value | $ 845,879 | $ 271,012
Gross unrealized losses, 12 months or more, amount | (163,950) | (12,885)
Held-to-maturity |  |
Amortized cost | 513,767 | 522,270
Gross unrealized gains | 0 | 1,648
Gross unrealized losses | (73,744) | (13,444)
Held-to-maturity investment securities | $ 440,023 | $ 510,474
Less than 12 months, number of issues | issue | 27 | 24
Less than 12 months, fair value | $ 290,803 | $ 330,477
Less than 12 months, amount | $ (41,864) | $ (7,835)
12 months or longer, number of issues | issue | 13 | 7
12 months or longer: fair value | $ 149,220 | $ 106,483
12 months or longer, amount | (31,880) | (5,609)
U.S. Treasury and federal agency obligations | American Savings Bank (ASB) |  |
Available-for-sale |  |
Amortized cost | 107,389 | 89,714
Gross unrealized gains | 0 | 803
Gross unrealized losses | (4,902) | (427)
Available-for-sale investment securities, at fair value | $ 102,487 | $ 90,090
Gross unrealized losses, less than 12 months, number of issues | issue | 17 | 4
Gross unrealized losses, less than 12 months, fair value | $ 102,487 | $ 44,827
Gross unrealized losses, less than 12 months, amount | $ (4,902) | $ (427)
Gross unrealized losses, 12 months or longer, number of issues | issue | 0 | 0
Gross unrealized losses, 12 months or longer, fair value | $ 0 | $ 0
Gross unrealized losses, 12 months or more, amount | 0 | 0
Held-to-maturity |  |
Amortized cost | 59,882 | 59,871
Gross unrealized gains | 0 | 168
Gross unrealized losses | (5,997) | (170)
Held-to-maturity investment securities | $ 53,885 | $ 59,869
Less than 12 months, number of issues | issue | 3 | 2
Less than 12 months, fair value | $ 53,885 | $ 39,594
Less than 12 months, amount | $ (5,997) | $ (170)
12 months or longer, number of issues | issue | 0 | 0
12 months or longer: fair value | $ 0 | $ 0
12 months or longer, amount | 0 | 0
Mortgage-backed securities | American Savings Bank (ASB) |  |
Available-for-sale |  |
Amortized cost | 2,606,904 | 2,482,618
Gross unrealized gains | 467 | 6,511
Gross unrealized losses | (322,185) | (51,206)
Available-for-sale investment securities, at fair value | $ 2,285,186 | $ 2,437,923
Gross unrealized losses, less than 12 months, number of issues | issue | 180 | 120
Gross unrealized losses, less than 12 months, fair value | $ 1,409,947 | $ 1,845,243
Gross unrealized losses, less than 12 months, amount | $ (158,235) | $ (38,321)
Gross unrealized losses, 12 months or longer, number of issues | issue | 66 | 18
Gross unrealized losses, 12 months or longer, fair value | $ 845,879 | $ 271,012
Gross unrealized losses, 12 months or more, amount | (163,950) | (12,885)
Held-to-maturity |  |
Amortized cost | 453,885 | 462,399
Gross unrealized gains | 0 | 1,480
Gross unrealized losses | (67,747) | (13,274)
Held-to-maturity investment securities | $ 386,138 | $ 450,605
Less than 12 months, number of issues | issue | 24 | 22
Less than 12 months, fair value | $ 236,918 | $ 290,883
Less than 12 months, amount | $ (35,867) | $ (7,665)
12 months or longer, number of issues | issue | 13 | 7
12 months or longer: fair value | $ 149,220 | $ 106,483
12 months or longer, amount | (31,880) | (5,609)
Corporate bonds | American Savings Bank (ASB) |  |
Available-for-sale |  |
Amortized cost | 44,447 | 30,625
Gross unrealized gains | 0 | 655
Gross unrealized losses | (3,018) | (102)
Available-for-sale investment securities, at fair value | $ 41,429 | $ 31,178
Gross unrealized losses, less than 12 months, number of issues | issue | 5 | 1
Gross unrealized losses, less than 12 months, fair value | $ 41,429 | $ 12,780
Gross unrealized losses, less than 12 months, amount | $ (3,018) | $ (102)
Gross unrealized losses, 12 months or longer, number of issues | issue | 0 | 0
Gross unrealized losses, 12 months or longer, fair value | $ 0 | $ 0
Gross unrealized losses, 12 months or more, amount | 0 | 0
Mortgage revenue bonds | American Savings Bank (ASB) |  |
Available-for-sale |  |
Amortized cost | 15,165 | 15,427
Gross unrealized gains | 0 | 0
Gross unrealized losses | 0 | 0
Available-for-sale investment securities, at fair value | $ 15,165 | $ 15,427
Gross unrealized losses, less than 12 months, number of issues | issue | 0 | 0
Gross unrealized losses, less than 12 months, fair value | $ 0 | $ 0
Gross unrealized losses, less than 12 months, amount | $ 0 | $ 0
Gross unrealized losses, 12 months or longer, number of issues | issue | 0 | 0
Gross unrealized losses, 12 months or longer, fair value | $ 0 | $ 0
Gross unrealized losses, 12 months or more, amount | $ 0 | $ 0

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