The implied volatility is generally equal to or significantly greater than the forecasted volatility; for instance, the BSM implied volatility is, in general, an upward biased estimator. Indeed, by selling implied volatility a risk premium is provided because of the many expected and unexpected events that may occur. Moreover, market microstructure posits that implied volatility should be biased high because market makers profit from the bid-ask spread in the options by slightly raising their quotes (i.e., going slight long volatility exposure particularly on the downside). However, this absolutely doesn’t mean that it is always possible to profit by selling implied volatility