An important aim of the QE policies pursued in the United States, the United Kingdom, and Japan has been to encourage risk taking and to raise asset prices as the means to stimulate aggregate demand. The question that now needs to be asked is whether these policies may have given rise to excessive risk taking, overleveraging, and bubbles in asset and credit markets. In this context, one has to wonder whether historically low yields on junk bonds in the industrialized countries now understate the risk of owning those bonds. . . . One also has to wonder whether yields on sovereign bonds in the European periphery have become disassociated from those countries’ underlying economic fundamentals and whether global equity valuations have not become excessively rich.