Mitchell Craig Warachka

Streaks in Earnings Surprises and the Cross-Section of Stock Returns

The gamblers fallacy [Rabin, M. 2002. Inference by believers in the law of small numbers. Quart. J. Econom.117(3) 775--816] predicts that trends bias investor expectations. Consistent with this prediction, we find that investors underreact to streaks of consecutive earnings surprises with the same sign. When the most recent earnings surprise extends a streak, post-earnings-announcement drift is strong and significant. In contrast, the drift is negligible following the termination of a streak. Indeed, streaks explain about half of the post-earnings-announcement drift in our sample. Our results are robust to more general definitions of trends than streaks and a battery of control variables including the magnitude of earnings surprises and their autocorrelation. Overall, post-earnings-announcement drift has a significant time-series component that is consistent with the gamblers fallacy. This paper was accepted by Wei Xiong, finance.

The impact of transaction duration, volume and direction on price dynamics and volatility

We explore the role of trade volume, trade direction, and the duration between trades in explaining price dynamics and volatility using an Asymmetric Autoregressive Conditional Duration model applied to intraday transactions data. Our results suggest that volume, direction and duration are important determinants of price dynamics, while duration is also an important determinant of volatility. However, the impact of volume and direction on volatility is marginal after controlling for duration, and the impact of volume on volatility appears to be confined to periods of infrequent trading.

Forecast Accuracy Uncertainty and Momentum

We demonstrate that stock price momentum and earnings momentum can result from uncertainty surrounding the accuracy of cash flow forecasts. Our model has multiple information sources issuing cash flow forecasts for a stock. The investor combines these forecasts into an aggregate cash flow estimate that has minimal mean-squared forecast error. This aggregate estimate weights each cash flow forecast by the estimated accuracy of its issuer, which is obtained from their past forecast errors. Momentum arises from the investor gradually learning about the relative accuracy of the information sources and updating their weights. Empirical tests validate the models prediction of stronger momentum in stocks with large information weight fluctuations and high forecast dispersion. We also identify return predictability attributable to changes in the information weights.

Implied Measures of Relative Fund Performance

Abstract We evaluate the relative performance of funds by conditioning their returns on the cross-section of portfolio characteristics across fund managers. Our implied procedure circumvents the need to specify benchmark returns or peer funds. Instead, fund-specific benchmarks for measuring selection and market timing ability are constructed. This technique is robust to herding as well as window dressing and mitigates survivorship bias. Empirically, the conditional information contained in portfolio weights defined by industry sectors, assets, and geographical regions is important to the assessment of fund management. For each set of portfolio characteristics, we identify funds with success at either selecting securities or timing-the-market.

Incorporating Diversification into Risk Management

Risk measurement is of fundamental importance to financial practice. Given the widespread usage of Value-at-Risk (VaR), firms actively manage their risk. Unfortunately, VaR is not derived from fundamental economic principles and may lead to sub-optimal decisions as shown by Shapiro and Basak (2001).