[First of all, i would like to apologized me for possible language errrors, because i'm from Europe and English is not my mothertongue.] The B&S formula creates "fair option values" as long as the inputs are correct. So the formula predicts that buying or selling options randomly is going to break even in the long run. So buying (or selling) is NOT superior to selling (buying) the same option. That's what the theory says. So if i say that i'm going the sell put options every month without paying attention to implied volatility or a directional market view, what would be the result? The option theorist would say that you will break even in the long run. My point is now, that the practice shows that this is not the case. I refer to the "^put index". The CBOE put/write index systematically sells one-month ATM s&p put options since 1986. The put index has earned a higer return than de S&P 500 (10% average annual return). These result are not in line with what the B&S formula would say? Selling index put option during 26 years was a very profitable strategy and not a 'break-even-strategy'? What are the reason(s) for this deviation (inconsistency)? I have some ideas but i would like to know what you are thinking?