Inspired by Google’s PageRank, the authors of a new paper create DebtRank, a measure of connection centrality. The vertical axis in the following diagram shows DebtRank (centrality) the horizontal axis asset shows size relative to the total network and the color indicates fragility/leverage. Institutions such as Wachovia, RBS and Barclays were relatively small but because of their centrality and fragility they imposed big risks on the system.