This study shows that U.S. individual investors hold under-diversified portfolios, where the level of under-diversification is greater among younger, low-income, less-educated, and less-sophisticated investors. The level of under-diversification is also correlated with investment choices that are consistent with over-confidence, trend-following behavior, and local bias. Furthermore, investors who over-weight stocks with higher volatility and higher skewness are less diversified. In contrast, there is little evidence that portfolio size or transaction costs constrains diversification. Under-diversification is costly to most investors, but a small subset of investors under-diversify because of superior information.

This paper examines the characteristics and pricing of stocks that are actively traded by speculative retail investors. We find that stocks with high retail trading proportion (RTP) have strong lottery features and they attract retail investors with strong gambling propensity. Furthermore, these stocks tend to be overpriced and earn significantly negative alpha. The average monthly return differential between the extreme RTP quintiles is −0.60%. This negative RTP premium is stronger among stocks that have lottery features or arelocated in regions where people exhibit stronger gambling propensity. Collectively, these results indicate that speculative retail trading affects stock prices.

This paper examines the investment decisions of older individual investors. We find that older and experienced investors are more likely to follow rules of thumb that reflect greater investment knowledge. However, older investors are less effective in applying their investment knowledge and exhibit worse investment skill, especially if they are less educated, earn lower income, and belong to minority racial/ethnic groups. Overall, the adverse effects of aging dominate the positive effects of experience. These results indicate that older investors' portfolio decisions reflect greater knowledge about investing, but investment skill deteriorates with age due to the adverse effects of cognitive aging.

We examine whether corporate bankruptcies influence bank loan characteristics of geographically proximate firms. Controlling for industry contagion and local economic conditions, firms headquartered near a bankruptcy event experience a 7 basis point increase in loan spreads. The effect is transitory and cannot be fully explained by local correlated information or lenders’ financial health. Instead, the effect is more pronounced for informationally opaque bankruptcies and borrowers, and weakened among loans with relationship lenders and lenders with significant local presence.

We find that forecast revisions by analysts with more favorable surnames elicit stronger market reactions. The effect is stronger among firms with lower institutional ownership and for analysts with non-American first names. Following the 9/11 terrorist attacks, and France and Germany's opposition to the Iraq War, revisions by analysts with Middle Eastern and French or German surnames, respectively, generated weaker market reaction. Surname favorability is not associated with forecast quality, but it has complementary effects with forecast performance on analysts’ career outcomes. Surname favorability mitigates under-reaction to forecast revisions. These findings are distinct from the effects of ethnic, cultural proximity, or in-group bias.

Using Internet search volume of dividend-related keywords to measure investor preference for dividends that varies over time and across states, we show that dividend sentiment affects corporate policies and asset prices. Investors search more for dividends when economic conditions are poor, with the peak volume reached during the recent COVID-19 pandemic. Firms initiate or increase dividends when dividend sentiment is stronger, especially in regions with strong dividend sentiment. Shifts in dividend sentiment predict higher investor demand for dividends and higher returns for high dividend stocks. Further, mutual funds that pay high dividends receive more inflows when dividend sentiment is stronger.

We show that the personal traits of analysts, as revealed by their political donations, influence their forecasting behavior and stock prices. Analysts who contribute primarily to the Republican Party adopt a more conservative forecasting style. Their earnings forecast revisions are less likely to deviate from the forecasts of other analysts and are less likely to be bold. Their stock recommendations also contain more modest upgrades and downgrades. Overall, these analysts produce better quality research, which is recognized and rewarded by their employers, institutional investors, and the media. Stock market participants, however, do not fully recognize their superior ability as the market reaction following revisions by these analysts is weaker.

Using Internet search volume for lottery to capture gambling sentiment shifts, we show that when the overall gambling sentiment is strong, investor demand for lottery stocks increases, these stocks earn positive short-run abnormal returns, managers are more likely to split stocks to cater to the increased demand for low-priced lottery stocks, and initial public offerings (IPOs) earn higher first day returns. Further, the sentiment-return relation is stronger among low institutional ownership firms, headquartered in regions where gambling is more acceptable and local bias is stronger. These results suggest that gambling sentiment has a spillover effect on the stock market.

We study the aggregate impact of information spillovers emerging from industry star firms. Changes in stars’ relative earnings growth predict future earnings growth, consensus earnings surprises, and job postings of same-industry nonstar firms. Star-firm performance also predicts industry-level GDP and employment growth. Price markup and innovation spillovers are potential channels underlying these patterns. Our results further show that this performance predictability is not fully incorporated into nonstars’ stock prices. A long–short portfolio based on star firms’ earnings growth earns an annualized 6-factor alpha of 8.7%. Together, our findings provide consistent evidence of the economic importance of star firms.