The shock of the new

Alan Greenspan is still puzzled. It is four months since the president of the Federal Reserve Board talked about the «conundrum» of low bond yields, but he seems to have made little intellectual progress. In a speech to the International Monetary Conference in Beijing, Greenspan ruled out four hypotheses. He gave good reasons to dismiss coming economic weakness, pension fund buying, demographic forces and buying by foreign authorities. But when it came to offering his own hypothesis, Greenspan c...