Bank credit and money creation on payment networks : a structural analysis of externalities and key players

This paper documents a strong connection between payment system and credit supply. The dual role of deposits as financing instruments for banks and means of payment for bank customers implies spillover effects of bank lending. After a bank finances loans with new deposits, the deposit holders' payments cause reserves and deposits to flow from the lending bank to the payees' banks. The change in liquidity conditions for both banks and their customers gives rise to two opposing forces that generate respectively strategic complementarity and strategic substitution in banks' lending decisions. We model bank lending through a linear-quadratic game on a random graph of payment flows and structurally estimate the spillover effects using Fedwire data to quantify the probability distribution of payment-flow network. Payment network externalities reduce the average level of aggregate credit supply by 9% while amplify the volatility by 20%. We identify a small subset of banks that have a disproportionately large influence on credit supply due to their special positions in the payment-flow network