问答题 If there is a sacred belief among investors, it is that equities are the best asset for the long run. Buy a diversified portfolio, be patient and rewards will come. Holding cash or government bonds may offer safety in the short term but leaves the investor at risk from inflation over longer periods. Such beliefs sit oddly with the performance of the Tokyo stock market, which peaked at the end of 1989 and is still 75% below its high. Over the 30 years ending in 2010, a “long run” by any standards, American equities beat government bonds by less than a percentage point a year. In the developed world, the period since the turn of the millennium has been a particular disappointment. Since the end of 1999 the return on American equities has been 7. 6 percentage points a year lower than that on government bonds. That has left many corporate and public pension funds in deficit and many people with private pensions facing a delayed, or poorer, retirement. Understanding why equities have let investors down over the past decade will help them work out what to expect in the future. The long-term faith in equities is based on the theory that investors should be rewarded for the riskiness of shares with a higher return, known as the “equity risk premium” (ERP) . That risk comes in two forms. The first is that shareholders get paid only when other claimants on a company’ s cashflow, such as workers, the taxman and creditors, have received their due. Profits and dividends are thus highly variable and can disappear altogether when times get tough. The second risk is that share prices are volatile, more so than bond prices. Since 1926 there have been seven calendar years when American equity investors have suffered a loss of more than 20%; investors in Treasuries have suffered no such calamitous years.无