Does conservatism in analyst earnings predictions cause mispricing? If it does, then we should find that stocks associated with recent positive earnings surprises should experience higher returns than the overall market, while stocks associated with recent negative earnings surprises should earn lower returns than the overall market. Figure 4-2, taken from an article by the late Victor Bernard and Jacob Thomas (1989), summarizes the evidence. The figure shows the behavior of
horizons being too short. They call this reluctance myopic loss aversion. Benartzi and Thaler suggest that investors who are prone to myopic loss aversion can increase their comfort with equities by monitoring the performance of their portfolios less frequently, no more than once a year. It appears that investors who hold individual stocks monitor those stocks much more frequently than that. John Pound and Robert Shiller (1989) found that individual investors spent over a halfhour per day following the most recent stock they bought. Nicholas Barberis, Ming Huang, and Tano Santos (1999) use the Thaler-Johnson “house money effect” discussed in chapter 3, to take the argument one step further. They suggest that after a market run up, the house money effect kicks in, raising investors’ tolerance for risk, and lowering the equity premium. In a downturn the reverse occurs.