How Do Volatility and Return Series Interact?

Literature in the last forty years is swamped with a myriad of studies on the relationshipbetween asset returns and volatility. Although the correlation between these two variablesis already well-documented, our knowledge regarding their causal relationship remains limited. This study formally investigates the true dynamic relationship between the VIX implied volatility index and the S&P500 returns. Innovation accounting results indicate strong influence of S&P500 returns on VIX but not vice versa. Plus, unexpected S&P500 losses tend to increase VIX temporarily, while return shocks in general have permanent impact on VIX in the adverse direction of the shock.