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Abstract:
We propose a theory based on investor overconfidence and biased self-attribution to explain several of the securities returns patterns that seem anomalous from the perspective of efficient markets with rational investors. The theory is based on two premises derived from evidence in psychological studies. The first is that individuals are overconfident about their ability to evaluate securities, in the sense that they overestimate the precision of their private information signals. The second is that investors' confidence changes in a biased fashion as a function of their decision outcomes. The first premise implies overreaction to private information arrival and underreaction to public information arrival. This is consistent with (1) post-corporate event and post-earnings announcement stock price 'drift', (2) negative long-lag autocorrelations (long-run 'overreaction'), and (3) excess volatility of asset prices. Adding the second premise leads to (4) positive short-lag autocorrelations ('momentum'), and (5) short-run post-earnings announcement 'drift,' and negative correlation between future stock returns and long-term measures of past accounting performance. The model also offers several untested empirical implications and implications for corporate financial policy.

Abstract:
We review extensive evidence about how psychological biases affect investor behavior and prices. Systematic mispricing probably causes substantial resource misallocation. We argue that limited attention and overconfidence cause investor credulity about the strategic incentives of informed market participants. However, individuals as political participants remain subject to the biases and self-interest they exhibit in private settings. Indeed, correcting contemporaneous market pricing errors is probably not government's relative advantage. Government and private planners should establish rules and procedures ex ante to improve choices and efficiency, including disclosure, reporting, advertising, and default-option-setting regulations. Especially, government should avoid actions that exacerbate investor biases.

Abstract:
We review extensive evidence about how psychological biases affect investor behavior and prices. Systematic mispricing probably causes substantial resource misallocation. We argue that limited attention and overconfidence cause investor credulity about the strategic incentives of informed market participants. However, individuals as political participants remain subject to the biases and self-interest they exhibit in private settings. Indeed, correcting contemporaneous market pricing errors is probably not government's relative advantage. Government and private planners should establish rules ex ante to improve choices and efficiency, including disclosure, reporting, advertising, and default-option- setting policies. Especially, government should avoid actions that exacerbate investor biases.

Abstract:
We decompose stock returns into components attributable to tangible and intangible information. A firm's tangible return is the component of its return attributable to fundamental accounting-performance information, and its intangible return is the component which is orthogonal to this information. Our evidence indicates that intangible information reliably predicts future stock returns. However, in contrast to previous research, we find that tangible returns have no forecasting power. The premia associated with intangible information pose challenges for both traditional asset pricing models and models based on psychological factors.

Abstract:
Previous empirical studies suggest a negative relationship between prior 3-5 year fundamental performance and future returns: distressed firms outperform more profitable firms. In fact, we show here that after controlling for past stock returns firms with higher past fundamental returns actually outperform weaker firms. Our results are consistent with investors reacting appropriately to tangible information (defined as information which can be extracted from financial statements), but overreacting to intangible information. We explain these findings with a simple model based on the behavioral finding that investors are more overconfident about their ability to interpret intangible information. Finally, we reconcile our results with previous studies, and show that firms which grow through shareissuance activity experience low future returns, while firms that grow through increased profitability do not.

Abstract:
This paper offers a model in which asset rices reflect both covariance risk and misperceptions of firms' prospects, and in which arbitrageurs trade against mispricing. In equilibrium, expected returns are linearly related to both risk and mispricing measures (e.g., fundamental/price ratios). With many securities, mispricing of idiosyncratic value components diminishes but systematic mispricing does not. The theory offers untested empirical implications about volume, volatility, fundamental/price ratios, and mean returns, and is consistent with several empirical findings. These include the ability of fundamental/price ratios and market value to forecast returns, and the domination of beta by these variables in some studies.

Abstract:
This paper offers a multisecurity model in which prices reflect both covariance risk and misperceptions of firms' prospects, and in which arbitrageurs trade to profit from mispricing. We derive a pricing relationship in which expected returns are linearly related to both risk and mispricing variables. The model thereby implies a multivariate relation between expected return, beta, and variables that proxy for mispricing of idiosyncratic components of value tends to be arbitraged away but systematic mispricing is not. The theory is consistent with several empirical findings regarding the cross-section of equity returns, including: the observed ability of fundamental/price ratios to forecast aggregate and cross-sectional returns, and of market value but not non-market size measures to forecast returns cross-sectionally; and the ability in some studies of fundamental/price ratios and market value to dominate traditional measures of security risk. The model also offers several untested empirical implications for the cross-section of expected returns and for the relation of volume to subsequent volatility.

Abstract:
We provide a model with overconfident risk neutral investors, and therefore no risk premia, in which a price-based portfolio such as HML earns positive expected returns and loads on fundamental macroeconomic variables. Furthermore, loadings on such portfolios are proxies for mispricing, and therefore forecast cross-sectional returns, even after controlling for characteristics such as book-to-market. Thus, an empirical finding that covariances incrementally predict returns does not distinguish rational factor pricing from a setting with no risk premia. The analysis reconciles the high risk (market betas) of low book-to-market firms with their low expected returns, and offers new empirical implications to distinguish alternative theories.

factor models, overconfidence, Fama-French factors, covariance risk

Abstract:
We propose a model of sequential bidding for a valuable object, such as a takeover target, when it is costly submit or revise a bid. An implication of the model is that bidding occurs in repeated jumps, a pattern that is consistent with certain types of natural auctions such as takeover contests. The jumps in bid communicate bidders' information rapidly, leading to contests that are completed with a small number of bids. The model provides several new results concerning revenue and efficiency relationships between different auctions, and provides an information-based interpretation of delays in bidding.

Abstract:
This paper explains why investors are likely to be overconfident and how this behavioral bias affects investment decisions. Our analysis suggests that investor overconfidence can potentially generate stock return momentum and that this momentum effect is likely to be the strongest in those stocks whose valuation requires the interpretation of ambiguous information. Consistent with this, we find that momentum effects are stronger for growth stocks than value stocks. A portfolio strategy based on this hypothesis generates strong abnormal returns that do not appear to be attributable to risk. Although these results violate the traditional efficient markets hypothesis, they do not necessarily imply that rational but uniformed investors, without the benefit of hindsight, could have actually achieved the returns. We argue that to examine whether unexploited profit opportunities exist, one must test for what we call adaptive-efficiency, which is a somewhat weaker form of market efficiency that allows for the appearance of profit opportunities in historical data, but requires these profit opportunities to dissipate when they become apparent. Our tests reject this notion of adaptive-efficiency.

Abstract:
Firm size and book-to-market ratios are both highly correlated with the returns of common stocks. Fama and French (1993) have argued that the association between these firm characteristics and their stock returns arises because size and book-to-market ratios are proxies for non-diversifiable factor risk. In contrast, the evidence in this paper indicates that the return premia on small capitalization and high book-to-market stocks does not arise because of the co-movements of these stocks with pervasive factors. It is the firm characteristics and not the covariance structure of returns that explain the cross-sectional variation in stock returns.

Abstract:
Firm sizes and book-to-market ratios are both highly correlated with the average returns of common stocks. Fama and French (1993) argue that the association between these characteristics and returns arises because the characteristics are proxies for non-diversifiable factor risk. In contrast, the evidence in this paper indicates that the return premia on small capitalization and high book-to-market stocks does not arise because of the co-movements of these stocks with pervasive factors. It is the characteristics rather than the covariance structure of returns that appear to explain the cross-sectional variation in stock returns.

Abstract:
Firm size and book-to-market ratios are both highly correlated with the returns of common stocks. Fama and French (1993) and others have argued that the association between these firm characteristics and their stock returns arises because size and book-to-market ratios are proxies for non-diversifiable factor risk. In contrast, the evidence in this paper indicates that the return premia on small capitalization and high book-to-market stocks does not arise because of the co-movements of these stocks with pervasive factors. It is the firm characteristics and not the covariance structure of returns that explain the cross-sectional variation in stock returns.

Abstract:
Japanese stock returns are even more closely related to their book-to-market ratios than are their U.S. counterparts, and thus provide a good setting for testing whether the return premia associated with these characteristics arise because the characteristics are proxies for covariance with priced factors. Our tests, which replicate the Daniel and Titman (1997) tests on a Japanese sample, reject the Fama and French (1993) three-factor model but fails to reject the characteristic model.

Abstract:
This paper offers a model in which asset prices reflect both covariance risk and misperceptions of firmsapos prospects, and in which arbitrageurs trade against mispricing. In equilibrium, expected returns are linearly related to both risk and mispricing measures (e.g., fundamental/price ratios). With many securities, mispricing of idiosyncratic value components diminishes but systematic mispricing does not. The theory offers untested empirical implications about volume, volatility, fundamental/price ratios, and mean returns, and is consistent with several empirical findings. These include the ability of fundamental/price ratios and market value to forecast returns, and the domination of beta by these variables in some studies.

Abstract:
We propose a theory of securities market under- and overreactions based on two well-known psychological biases: investor overconfidence about the precision of private information; and biased self-attribution, which causes asymmetric shifts in investors' confidence as a function of their investment outcomes. We show that overconfidence implies negative long-lag autocorrelations, excess volatility, and, when managerial actions are correlated with stock mispricing, public-event-based return predictability. Biased self-attribution adds positive short-lag autocorrelations ("momentum"), short-run earnings "drift," but negative correlation between future returns and long-term past stock market and accounting performance. The theory also offers several untested implications and implications for corporate financial policy.