Analysis is done using census tract codes. Tracts have income classifications, and zip codes do not. There may be several census tracts in a zip code and each can have a different income classification. For CRA analysis purposes stick with the census tracts. Zip codes may be some good marketing information.
Comparing deposits to loans by zip code will not be very useful for CRA purposes. The loan to deposit ratio of the your bank each quarter, will be averaged and compared to other peer institutions.
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