<prompt> Human: Next month, something very dramatic is going to happen to most stock mutual funds. In fact, its already started to happen. The dramatic event is this: Those funds will hit the three-year anniversary of the nadir of the market in March 2009. And that means their three-year-return numbers will start to look amazingly good. Think Im being hyperbolic? Think again. The most widely held mutual fund -- the Vanguard Total Stock Market Index Fund -- is up at an annual rate of 30.23 percent from March 6, 2009 the trough, by some measurements through the end of last month, January 31, 2012. Dial those numbers back by six months -- from before the 2008 decline to before the big 2012 gains -- and the average annual returns for the same fund are 0.91 percent for the three-year period between August 29, 2008 and August 30, 2011.  <response>: This is why 1, 3, 5, 10, and 15 year returns are important to view as a whole rather than focus on one time period. And more importantly, not be fixated on the gross return number but relative to the benchmark, index, inflation, the risk-free rate and an alternative investments you can use i.e. compare stock returns to bonds and vice versa 