Until this week at least, one of the big puzzles of the year for many investors was squaring a 10-15% surge in equity indices with little or no movement in rock-bottom U.S., German and UK government bond yields. To the extent that both markets reflect expectations for future economic activity, then one of them looks wrong. The pessimists, emboldened by the superior predictive powers of the bond market over recent decades, claim the persistence of super low U.S. Treasury, German bund and British gilt yields reveals a deep and pervasive pessimism about global growth for many years to come. Those preferring the sunny side up reckon super-low yields are merely a function of central bank bond buying and money printing — and if those policies are indeed successful in reflating economies, then equity bulls will be proved correct in time. A market rethink on the chances for another bout of U.S. Federal Reserve bond-buying after upbeat Fed statements and buoyant U.S. economic numbers over the past week also nods to the latter argument.