Traditional and Shadow Banks

We propose a theory of the coexistence of traditional and shadow banks. In our model, shadow banks escape the costly regulation traditional banks must comply with, but forgo deposit insurance, which traditional banks can rely upon. In a crisis, shadow banks repay their creditors by selling assets at fire-sale prices to traditional banks, which fund these purchases with insured deposits. Our model is consistent with several facts from the 2007 financial crisis. The analysis implies an increase in traditional banks' debt capacity leads to an increase in the relative size of the shadow banking sector.