The paper explores the issue of macro-prudential policies in the light of empirical evidence on the determinants of bank systemic risk, and the effectiveness of capital controls. In many ways this reflects a step back in time towards sector approaches to monetary policy that were so prevalent in the 1960s, 1970s and early 1980s. Complexity and interdependence is such that proposals on these issues should be treated with care until much more is understood about the issue.