Reflections on the Efficient Market Hypothesis: 30 Years Later

In recent years financial economists have increasingly questioned the efficient market hypothesis. But surely if market prices were often irrational and if market returns were as predictable as some critics have claimed, then professionally managed investment funds should easily be able to outdistance a passive index fund. This paper shows that professional investment managers, both in The U.S. and abroad, do not outperform their index benchmarks and provides evidence that by and large market prices do seem to reflect all available information.     

Bank CEO materialism: Risk controls,culture and tail risk

We investigate how the prevalence of materialistic bank CEOs has evolved over time, and how risk management policies, non-CEO executives’ behavior and tail risk vary with CEO materialism. We document that the proportion of banks run by materialistic CEOs increased significantly from 1994 to 2004, that the strength of risk management functions is significantly lower for banks with materialistic CEOs, and that non-CEO executives in banks with materialistic CEOs insider trade more aggressively around government intervention during the financial crisis. Finally, we find that banks with materialistic CEOs have significantly more downside tail risk relative to banks with non-materialistic CEOs.     

The Credit Channel at the Zero Lower Bound through the Lens of Equity Prices

This study examines the impact of unconventional monetary policies on the stock market when the short‐term nominal interest rate is stuck at the zero lower bound (ZLB). Unconventional monetary policies appear to have significant effects on stock prices and the effects differ across stocks. In agreement with existing credit channel theories, I find that firms subject to financial constraints react more strongly to unconventional monetary policy shocks [especially large‐scale asset purchases (LSAPs)] than do less constrained firms. These results imply that the credit channel is as important as the interest rate channel in the transmission of unconventional monetary policies at the ZLB.     

Timing of earnings restatements: CEO equity compensation and market reaction

This study investigates the impact of chief executive officers’ (CEO) compensation on their choices regarding the timing of earnings restatements. The results indicate a negative relationship between options exercised and lags in disclosing the restated earnings, suggesting that managers who exercise options in a given year tend to release information quickly. This effect is more pronounced if the options are exercised after the dark period. We also find that the market penalises longer lags in the restatement disclosure. It seems that the CEO would try to optimise the timing of information release so as to balance the costs and benefits.     

The Response of Equity Prices to Movements in Long‐Term Interest Rates Associated with Monetary Policy Statements: Before and After the Zero Lower Bound

Monetary policy actions since 2008 have influenced long‐term interest rates through forward guidance and quantitative easing. I propose a strategy to identify the comovement between interest rate and equity price movements induced by monetary policy when an observable representing policy changes is not available. A decline in long‐term interest rates induced by monetary policy statements has a larger positive effect on equity prices prior to 2009 than in the subsequent period. This change appears to reflect the impact of the zero lower bound on short‐term interest rates.     

REAL OPTIONS AND THE CROSS‐SECTION OF EXPECTED STOCK RETURNS

This paper surveys the theoretical literature investigating the effect of firms’ investment flexibility on the cross‐section of expected stock returns. Real options analysis derives firms’ value‐maximizing investment policies as functions of exogenous fundamental drivers of profitability and calculates firms’ market values as functions of the same variables. These functions yield the relationship between expected stock returns and firm fundamentals. Several plausible explanations for the value premium – the high average stock returns earned by firms with high book‐to‐market ratios – emerge from this literature.     

Sell in May and Go Away: Evidence from China

Using the Chinese stock market data from 1997 to 2013, this paper examines the “Sell in May and Go Away” puzzle first identified by Bouman and Jacobsen (2002). We find strong existence of the Sell in May effect, robust to different regression assumptions, industries, and after controlling for the January or February effect. However, part of the puzzle is subsumed by the seasonal affective disorder effect. We then construct a trading strategy based on this puzzle, and find that it outperforms the buy-and-hold strategy and could resist the market downside risk during large recession periods.     

高管过度自信、研发投入跳跃与企业绩效——来自中国上市公司的经验证据

基于间断平衡理论和高阶梯队理论，以2007-2017年中国沪深两市902家制造企业为样本，实证分析研发投入跳跃对企业绩效的影响以及高管过度自信的调节作用。结果显示：研发投入正向跳跃和负向跳跃均有助于提升企业绩效，高管过度自信正向调节研发投入跳跃与企业绩效间的关系。引入高管过度自信这一重要高管特征作为调节变量，有助于重新认识管理者心理偏差对企业创新行为和绩效的影响，较好地弥补了研发投入跳跃对企业绩效影响机制的研究空缺，丰富了创新间断平衡理论研究。研究表明，企业应重视高管心理特征的影响并结合自身实际情况，合理选择研发投入策略以改善企业绩效。     

Individual stock sentiment beta and stock returns

Using the data in Chinese stock market, we measure the individual stock sentiment beta, which is defined as the sensitivity of individual stock returns to the individual stock sentiment changes. We demonstrate that stocks in the highest individual stock sentiment beta portfolio have significantly higher excess returns, CAPM alpha, Fama-French three-factor alpha and Fama-French five-factor alpha. Besides, we find that the high individual stock sentiment beta stocks are smaller, younger, more volatile stocks with higher price and higher market beta. After controlling for firm characteristic, the returns of High-Low individual stock sentiment beta portfolios are still significantly positive. Moreover, we show the effect of the individual stock sentiment beta on stock returns is positive and significant in different stock markets, in different sample periods, and in bull and bear market. Besides, the results of the Bayes-Stein individual stock sentiment beta are still stable.