We show that if a lead-lag relation exists between the option and spot markets, the implied volatility in option prices can be biased depending on the level of the true volatility; that is, the higher the true volatility, the more upward biased the implied volatility will be. We then test the...

We formulate a stylized model that admits volatility ambiguity to the Lucas framework. The model specifies an economically motivated ambiguity penalty function that makes volatility ambiguity quantifiable with χ2-statistics, and allows for analytical solutions. The addition of volatility...