This is really quite different, and is actually in practice more similar to selling options because of the bad effects of increased volatility. They massively underperform under heightened volatility, simulations are right there in prospectuses (in fact I'd go as far as to say that their expected value is 0 over the long run, but like very long, maybe 10-30 years). And yes you should always read the specs/prospectuses/10-Ks of the contracts/funds/companies that you buy.