I have a question. I always thought when everything else is equal, buying call options on an ETF has more upside potential than buying puts on its inverse ETF, that is if you think that ETF is about to go up, of course. But when I backtested some strategies, I found that the inverse ETF puts actually gave me much more profits. There is one caveat, the long ETF options traded at a much thinner volume, and the bid ask spreads were huge. Could this difference in profitability be explained by the larger slippage?