The US 10-year Treasury bond, the global investment benchmark, yields 3.25%, its highest level since June 2011. That may not sound like a harsh rate but US interest rates have been in steady decline for almost three decades. Over that period, with some bumps, notably the 1990s property crash and the dotcom boom and bust, what we have experienced is a fairly steep inflation in financial asset values. When bond yields go down, bond prices go up, borrowing is cheaper and investors pile into stocks, bonds and real estate.