We document persistent superior trading performance among a subset of individual investors. Investors classified in the top performance decile in the first half of our sample subsequently earn risk-adjusted returns of about 6% per year. These returns are not confined to stocks in which the investors are likely to have inside information, nor are they driven by illiquid stocks. Our results suggest that skilled individual investors exploit market inefficiencies (or perhaps conditional risk premiums) to earn abnormal profits, above and beyond any profits available from well-known strategies based on size, value, momentum, or earnings announcements. (JEL G11, G14, G40, G51) Received: October 11, 2020 Editorial decision: January 4, 2021 Editor: Jeffrey Pontiff

We present evidence of first impression bias among finance professionals in the field. Equity analysts’ forecasts, target prices, and recommendations suffer from first impression bias. If a firm performs particularly well (poorly) in the year before an analyst follows it, that analyst tends to issue optimistic (pessimistic) evaluations. Consistent with negativity bias, we find that negative first impressions have a stronger effect than positive ones. The market adjusts for analyst first impression bias with a lag. Finally, our findings contribute to the literature on experience effects. We show that a set of professionals in the field, equity analysts, apply U-shaped weights to their sequence of past experiences, with greater weight on first experiences and recent experiences than on intermediate ones.

We test how market overvaluation affects corporate innovation. Estimated stock overvaluation is strongly associated with measures of innovative inventiveness (novelty, originality, and scope), as well as research and development (R&D) and innovative output (patent and citation counts). Misvaluation affects R&D more via a nonequity channel than via equity issuance. The sensitivity of innovative inventiveness to misvaluation increases with share turnover and overvaluation. The frequency of exceptionally high innovative inputs/outputs increases with overvaluation. This evidence suggests that market overvaluation may generate social value by increasing innovative output and encouraging firms to engage in “moon shots.”