This study examines the impact of European Central Bank (ECB) monetary policy surprises on economic uncertainty and investor risk aversion. We identify four factors using a high-frequency event-study approach. These factors measure surprises regarding the current setting of policy rates (Target), the bank’s future policy path (Forward Guidance), and quantitative easing (QE). The fourth factor reflects unexpected news about future macroeconomic conditions. Our main finding is that quantitative tightening surprises, proxied by positive QE surprises, increase economic uncertainty and investor risk aversion. Additionally, we document the significant response of key macroeconomic variables to these surprises.

This article explores the role of the realized return distribution in the formation of the observed implied volatility smile using the framework of an adaptive expectations model. According to this framework investors update their expectations of future events, through which options are priced, by incorporating information from the underlying asset traded in the spot market. Our study is conducted at the level of cumulants which provide a complete description of investors expectations and can be considered as largely non-parametric with a minimal set of assumptions for the stochastic process that drives asset returns. The empirical results, based on the S&P 500 index, support the significance of the realized distribution in the formation of the implied volatility smile.

We investigate the link between stock and options markets during the 2008 U.S. short sale ban. First, we find definitive evidence that the ban indeed caused stock overvaluation. Second, we show that the short sale ban caused a significant increase in put-call parity violations only in the direction of the short sale constraints and it significantly enhanced the stock return predictability of put-call parity violations. Third, the overvaluation is really large. A portfolio formed on the trading signal that the put-call parity violation is in the top quintile underperforms the lowest quintile portfolio by a statistically and economically significant abnormal daily return of 5.6% during the short sale ban period. We employ a novel and rigorous method of using TAQ intraday data to ensure that our high-low violation arbitrage portfolio as well as the five Fama-French factors used to estimate the abnormal returns are implementable by a hypothetical investor exempt from the shorting ban.