[This article examines the issue of cross-sectional correlation in event studies. When there is event-date clustering, we find that even relatively low cross-correlation among abnormal returns is serious in terms of over-rejecting the null hypothesis of zero average abnormal returns. We propose a new test statistic that modifies the ¿ -statistic of Boehmer, Musumeci, and Poulsen (1991) to take into account cross-correlation and show that it performs well in competition with others, including the portfolio approach, which is less powerful than other alternatives under study. Also, our statistic is readily useable to test multiple-day cumulative abnormal returns.]

[Previous studies document that the stock returns of bond-issuing firms significantly underperform matched peers over the three to five years following issuance. We revisit this phenomenon and show that the underperformance is the result of an omitted return factor (a "bad model problem"). Debt issuers have significantly higher stock market liquidity than size and book-to-market matched counterparts, and differences in liquidity are largest for the worst-performing groups of issuers. When we additionally match on liquidity or when we include a liquidity factor in the model for expected returns, the evidence of underperformance disappears.]

[There is a strong inverse relation between insider trading and institutional demand the same quarter and over the previous year. Our analysis suggests a combination of factors contribute to this relation. First, institutional investors are more likely to provide the liquidity necessary for insiders to trade. Second, insiders are more likely to buy low valuation and low lag return stocks while institutions are attracted to the opposite security characteristics.Last, the results are consistent with the hypothesis that insiders are more likely to view their securities as overvalued (undervalued) following a period when institutions were net buyers (sellers).]

[This article advocates a theory of expectation formation that incorporates many of the central motivations of behavioral finance theory while retaining much of the discipline of the rational expectations approach. We provide a framework in which agents, in an asset pricing model, underparameterize their forecasting model in a spirit similar to Hong, Stein, and Yu (2007) and Barberis, Shleifer, and Vishny (1998), except that the parameters of the forecasting model and the choice of predictor are determined jointly in equilibrium. We show that multiple equilibria can exist even if agents choose only models that maximize (risk-adjusted) expected profits. A real-time learning formulation yields endogenous switching between equilibria. We demonstrate that a real-time learning version of the model, calibrated to U. S. stock data, is capable of reproducing regime-switching returns and volatilities, as recently identified by Guidolin and Timmermann]

[We show that, when stock prices are subject to stochastic mispricing errors, expected rates of return may depend not only on the fundamental risk that is captured by a standard asset pricing model, but also on the type and degree of asset mispricing, even when the mispricing is zero on average. Empirically, the mispricing induced return premium, either estimated using a Kaiman filter or proxied by the volatility and variance ratio of residual returns, is shown to be significantly associated with realized risk-adjusted returns.]

This article examines the issue of cross-sectional correlation in event studies. When there is event-date clustering, we find that even relatively low cross-correlation among abnormal returns is serious in terms of over-rejecting the null hypothesis of zero average abnormal returns. We propose a new test statistic that modifies the t-statistic of Boehmer, Musumeci, and Poulsen (1991) to take into account cross-correlation and show that it performs well in competition with others, including the portfolio approach, which is less powerful than other alternatives under study. Also, our statistic is readily useable to test multiple-day cumulative abnormal returns.

[Campbell, Lettau, Malkiel, and Xu (2001) document a positive trend in idiosyncratic volatility during the 1962-1997 period. We show that by 2003 volatility falls back to pre-1990s levels. Furthermore, we show that the increase and subsequent reversal is concentrated among firms with low stock prices and high retail ownership. This evidence suggests that the increase in idiosyncratic volatility through the 1990s was not a time trend but, rather, an episodic phenomenon, at least partially associated with retail investors. Results from cross-sectional regressions, conditional trend estimation, stock-split events, and "attentiongrabbing" events are consistent with a retail trading effect.]

Previous studies document that the stock returns of bond-issuing firms significantly underperform matched peers over the three to five years following issuance. We revisit this phenomenon and show that the underperformance is the result of an omitted return factor (a “bad model problem”). Debt issuers have significantly higher stock market liquidity than size and book-to-market matched counterparts, and differences in liquidity are largest for the worst-performing groups of issuers. When we additionally match on liquidity or when we include a liquidity factor in the model for expected returns, the evidence of underperformance disappears.

There is a strong inverse relation between insider trading and institutional demand the same quarter and over the previous year. Our analysis suggests a combination of factors contribute to this relation. First, institutional investors are more likely to provide the liquidity necessary for insiders to trade. Second, insiders are more likely to buy low valuation and low lag return stocks while institutions are attracted to the opposite security characteristics. Last, the results are consistent with the hypothesis that insiders are more likely to view their securities as overvalued (undervalued) following a period when institutions were net buyers (sellers).

Campbell, Lettau, Malkiel, and Xu (2001) document a positive trend in idiosyncratic volatility during the 1962–1997 period. We show that by 2003 volatility falls back to pre-1990s levels. Furthermore, we show that the increase and subsequent reversal is concentrated among firms with low stock prices and high retail ownership. This evidence suggests that the increase in idiosyncratic volatility through the 1990s was not a time trend but, rather, an episodic phenomenon, at least partially associated with retail investors. Results from cross-sectional regressions, conditional trend estimation, stock-split events, and “attention-grabbing” events are consistent with a retail trading effect.