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Regulatory Capital - Regulatory Capital Ratios (Details) $ in Thousands | Dec. 31, 2024 USD ($) | Dec. 31, 2023 USD ($)
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Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 421,639 | $ 375,440
Total capital to risk-weighted assets | 0.1208 | 0.1119
Total capital, Minimum Required for Capital Adequacy Purposes | $ 279,330 | $ 268,500
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.08 | 0.08
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 366,621 | $ 352,406
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Tier 1 capital | $ 329,796 | $ 293,338
Tier 1 capital to risk-weighted assets | 0.0945 | 0.0874
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 209,498 | $ 201,375
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.06 | 0.06
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 296,788 | $ 285,281
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Common equity tier 1 capital | $ 317,804 | $ 281,346
Common equity tier 1 capital to risk-weighted assets | 9.10% | 8.38%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 157,123 | $ 151,031
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 244,414 | $ 234,937
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Tier 1 leverage capital | $ 329,796 | $ 293,338
Tier 1 leverage capital to average assets | 0.0878 | 0.0843
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 150,256 | $ 139,145
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.04 | 0.04
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 150,256 | $ 139,145
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
First Business Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 417,965 | $ 376,310
Total capital to risk-weighted assets | 0.1197 | 0.1121
Total capital, Minimum Required for Capital Adequacy Purposes | $ 279,342 | $ 268,595
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.08 | 0.08
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 366,636 | $ 352,531
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 349,177 | $ 335,744
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.10 | 0.10
Tier 1 capital | $ 380,811 | $ 343,604
Tier 1 capital to risk-weighted assets | 0.1091 | 0.1023
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 209,506 | $ 201,446
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.06 | 0.06
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 296,801 | $ 285,382
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 279,342 | $ 268,595
Tier 1 capital to risk weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.08 | 0.08
Common equity tier 1 capital | $ 380,811 | $ 343,604
Common equity tier 1 capital to risk-weighted assets | 10.91% | 10.23%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 157,130 | $ 151,085
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 244,424 | $ 235,021
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 226,965 | $ 218,233
Common equity tier 1 capital to risk-weighted assets, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | 6.50% | 6.50%
Tier 1 leverage capital | $ 380,811 | $ 343,604
Tier 1 leverage capital to average assets | 0.1014 | 0.0987
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 150,207 | $ 139,262
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.04 | 0.04
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 150,207 | $ 139,262
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 187,759 | $ 174,077
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.05 | 0.05

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