How Do Analyst Recommendations Respond to Major News?
研究分析师在股价大幅波动后如何调整股票推荐，发现股价大跌后分析师更倾向于下调评级，且这种不对称性在考虑投行关系和羊群行为后依然存在，表明分析师存在乐观偏差。
Abstract We examine how analysts respond to public information when setting stock recommendations. We model the determinants of analysts' recommendation changes following large stock price movements. We find evidence of an asymmetry following large positive and negative returns. Following large stock price increases, analysts are equally likely to upgrade or downgrade. Following large stock price declines, analysts are more likely to downgrade. This asymmetry exists after accounting for investment banking relationships and herding behavior. This result suggests recommendation changes are “sticky” in one direction, with analysts reluctant to downgrade. Moreover, this result implies that analysts' optimistic bias may vary through time.