For each size category, the sum of equity held by banks with average assets greater than zero is divided by average assets. Equity equals Total Equity Capital call item RCFD3210. Total Assets equals call item RCFD2170. The asset classes are determined by using Average Total Assets call item RCFD2170 less than $300M. For more information and definition about the specific call item codes, please see http://www.federalreserve.gov/apps/mdrm/data-dictionary. This series is calculated by the Federal Reserve Bank of St. Louis using raw data that are collected by the FFIEC. Raw data can be found at https://cdr.ffiec.gov/public/.