A common claim is that 90% of options expire worthless, and that therefore it is better to be a seller of options than a buyer of options. This claim misstates a statistic published by the Chicago Board Options Exchange (CBOE), which is that only 10% of option contracts are exercised.
But just because only 10% are exercised does not mean the other 90% expire worthless. Instead, according to the CBOE, between 55% and 60% of options contracts are closed out prior to expiration. In other words, a seller who sold-to-open a contract will, on average, buy-to-close it 55-60% of the time, rather than holding the contract through to expiration.
So if 10% of options contracts end up being exercised, and 55-60% get closed out before expiration, that leaves only 30-35% of contracts that actually expire worthless. The big question is: of the 55-60% that get closed out before expiration, how often did the option seller profit, and how often did the option buyer profit?