We provide evidence on two alternative mechanisms of interaction between returns and volatilities: the leverage ef fect and the volatility feedback effect. We stress the importance of distinguishing between realized volatility and implied volatility and find that implied volatilities are...

In this paper, we provide evidence on two alternative mechanisms of interaction between returns and volatilities: the leverage effect and the volatility feedback effect. We stress the importance of distinguishing between realized volatility and implied volatility, and find that implied...

We provide evidence on two alternative mechanisms of interaction between returns and volatilities: the leverage ef fect and the volatility feedback effect. We stress the importance of distinguishing between realized volatility and implied volatility and find that implied volatilities are...

In this paper, we derive simple point-optimal sign-based tests in the context of linear and nonlinear regression models with fixed regressors. These tests are exact, distribution-free, robust against heteroskedasticity of unknown form, and they may be inverted to obtain confidence regions for...