Quantifying the Components of the Banks' Net Interest Margin

Using unique data sets on German banks, we decompose their net interest margin and quantify the different components by estimating the costs of the various functions they perform. We investigate three major functions: liquidity and payment management for customers, bearing credit risk, and term transformation. For 2013, the costs of liquidity and payment management correspond, in the median, to 47% of the net interest margin, with bearing of credit risk and earnings from term Transformation accounting for 12 and 37%, respectively