I have been reading the pros and cons of various models for calculating the theoretical value of options, but there are quite a bit of varying scenarios where one model works better than another. In regards to American style options that are within a week or so of expiration is there one model that tends to work better then most the others ?
Actually I am interested in calculating my exposure towards expiration. For instance AAPL made a 3+ Std Dev move today and I would like to find a decent way determine what effect that would have on a particular option. Obviously the implied volatility is probably going to be hard to approximate on a given strike, but I would like to use as practical and effective of a formula for such a scenario as I can. I know that some methods are more effective under certain circumstances than others... hence my reason for asking for an educated opinion of someone more experienced than I am.