Market e#ciency survives the challenge from the literature on long-term return anomalies. Consistent with the market e#ciency hypothesis that the anomalies are chance results, apparent overreaction to information is about as common as underreaction, and post-event continuation of pre-event abnormal returns is about as frequent as post-event reversal. Most important, consistent with the market e#ciency prediction that apparent anomalies can be due to methodology, most long-term return anomalies tend to disappear with reasonable changes in technique. # 1998 Elsevier Science S.A. All rights reserved.

Recent empirical research in finance has uncovered two families of pervasive regularities: underreaction of stock prices to news such as earnings announcements, and overreaction of stock prices to a series of good or bad news. In this paper, we present a parsimonious model of investor sentiment, or of how investors form beliefs, which is consistent with the empirical findings. The model is based on psychological evidence and produces both underreaction and overreaction for a wide range of parameter values. � 1998 Elsevier Science S.A. All rights reserved. JEL classification: G12; G14

We model a market populated by two groups of boundedly rational agents: “newswatchers” and “momentum traders.” Each newswatcher observes some private information, but fails to extract other newswatchers’ information from prices. If information diffuses gradually across the population, prices underreact in the short run. The underreaction means that the momentum traders can profit by trendchasing. However, if they can only implement simple (i.e., univariate) strategies, their attempts at arbitrage must inevitably lead to overreaction at long horizons. In addition to providing a unified account of under- and overreactions, the model generates several other distinctive implications.

This paper was developed with financial support from the SBF Bourse de Paris and the New York Stock Exchange, and the assistance of George Sofianos, Bill Tschirhart, and Didier Davidoff is gratefully acknowledged. We appreciate comments received on this paper from Anthony Boardman, Bernardo Bortolotti, Narjess Boubakri, JeanClaude Cosset, Kathy Dewenter, Alexander Dyck, Ivan Ivanov, Ranko Jelic, Claude Laurin, Marc Lipson, Luis Lopez-Calva, John McMillan (the editor), Harold Mulherin, Rob Nash, John Nellis, David Newberry, David Parker, Enrico Perotti, Annette Poulsen, Ravi Ramamurti, Susan Rose-Ackerman, Nemat Shafik, Mary Shirley, Aidan Vining and three anonymous referees. Additionally, we appreciate comments received from participants at the NYSE/Paris Bourse Global Equity Markets conference (Paris, December 1998), the Harvard Institute for International Development Privatization Workshop (June 2000), the International Federation of Stock Exchanges' Third Global Emerging Markets Conference (Istanbul, April 2000), four World Bank and/or International Finance Corporation meetings, two OECD conferences (Paris and Beijing), the 1999 Conference on Privatization and the Kuwaiti Economy in the Next Century, the 1998 Financial Management Association meeting, the 1999 European Financial Management Association meeting, the Fondazione ENI Enrico Mattei (FFEM), the Swiss Banking Institute and Credit Suisse, and seminars at the City University Business School (London), London Guildhall University and the University of Oklahoma. All remaining errors are the authors' alone. Please address correspondence to: William L. Megginson Price College of Business 307 West Brooks, 205A Adams Hall The University of Oklahoma Norman, OK 73019-4005 Tel: (405) 325-2058; Fax: (405) 325-1957 e-mail:...

We analyze tests for long-run abnormal returns and document that two approaches yield well-specified test statistics in random samples. The first uses a traditional event study framework and buy-and-hold abnormal returns calculated using carefully constructed reference portfolios. Inference is based on either a skewnessadjusted t-statistic or the empirically generated distribution of long-run abnormal returns. The second approach is based on calculation of mean monthly abnormal returns using calendar-time portfolios and a time-series t-statistic. Though both approaches perform well in random samples, misspecification in nonrandom samples is pervasive. Thus, analysis of long-run abnormal returns is treacherous. COMMONLY USED METHODS TO TEST for long-run abnormal stock returns yield misspecified test statistics, as documented by Barber and Lyon ~1997a! and Kothari and Warner ~1997!. 1 Simulations reveal that empirical rejection levels routinely exceed theoretical rejection levels in these tests. In combination, these papers highlight three causes for this misspecification. First, the

It is well known that firms are more likely to issue equity when their market values are high, relative to book and past market values, and to repurchase equity when their market values are low. We document that the resulting effects on capital structure are very persistent. As a consequence, current capital structure is strongly related to historical market values. The results suggest the theory that capital structure is the cumulative outcome of past attempts to time the equity market.

The share of equity issues in total new equity and debt issues is a strong predictor of U.S. stock market returns between 1928 and 1997. In particular, firms issue relatively more equity than debt just before periods of low market returns. The equity share in new issues has stable predictive power in both halves of the sample period and after controlling for other known predictors. We do not find support for efficient market explanations of the results. Instead, the fact that the equity share sometimes predicts significantly negative market returns suggests inefficiency and that firms time the market component of their returns when issuing securities.

Seasoned equity issuers can raise reported earnings by altering discretionary accounting accruals. We find that issuers who adjust discretionary current accruals to report higher net income prior to the o#ering have lower post-issue long-run abnormal stock returns and net income. Interestingly, the relation between discretionary current accruals and future returns (adjusted for firm size and book-to-market ratio) is stronger and more persistent for seasoned equity issuers than for non-issuers. The evidence is consistent with investors naively extrapolating pre-issue earnings without fully adjusting for the potential manipulation of reported earnings. # 1998 Elsevier Science S.A. All rights reserved.

This paper addresses the following basic capital budgeting question: Suppose that crosssectional differences in stock returns can be predicted based on variables other than beta (e.g., book-to-market), and that this predictability reflects market irrationality rather than compensation for fundamental risk. In this setting, how should companies determine hurdle rates? I show how factors such as managerial tune horizons and financial constraints affect the optimal hurdle rate. Under some circumstances, beta can be useful as a capital budgeting tool, even if it is of no use in predicting stock returns.

We use a simple model to outline the conditions under which corporate investment is sensitive to non-fundamental movements in stock prices. The key prediction is that stock prices have a stronger impact on the investment of “equity dependent ” firms – firms that need external equity to finance marginal investments. Using an index of equity dependence based on the work of Kaplan and Zingales [1997], we find support for this hypothesis. In particular, firms that rank in the top quintile of the KZ index have investment that is almost three times as sensitive to stock prices as firms in the bottom quintile.