The topology of interbank payment flows

We explore the network topology of the interbank payments transferred between commercial banks over the Fedwire®® Funds Service. We find that the network has both a low average path length and low connectivity. The network includes a tightly connected core of banks to which most other banks connect. The degree distribution is scale free over a substantial range. We find that the properties of the network changed considerably in the immediate aftermath of the events of September 11, 2001.