Check out your local community banks.
when you drop below the money center banks, the regional banks tend to be Republican, as may be seen below: (The former percentage is Democrat; the latter Republican)
Regions Financial 42.20% 57.80%
1st Financial Bank USA 18.30% 81.70%
Midfirst Bank 38.30% 61.60%
Citizens First Bank 0.20% 99.80%
Woodforest Financial Group 0% 100.00%
First National Bank 5.40% 94.30%
Citizens Financial Group 54.20% 45.60%
Banco Bilbao Vizcaya Argentaria 35.10% 64.90%
Ally Financial 45.90% 54.00%
Huntington Bancshares 45.60% 54.30%
I suspect that, if you were to eliminate locally owned banks outside the Northeast and West Coast, banker contributions are strongly Republican.