Recent research suggests a point beyond which the benefits of financial development diminish, and further development can even hurt growth. This column describes how a negative relationship between credit and growth emerged strongly after 1990 and was particularly pronounced in the Eurozone, consistent with the notion that an overgrown financial sector weakens economic growth potential. It also argues that slower growth leads to more rapid financial sector expansion. Policymakers need to be aware of the possibility that causality runs in both directions.