There's a part that refers to the research, but the way they describe it sounds confused, like the author doesn't understand the domain. (Or maybe I'm not using

There's a part that refers to the research, but the way they describe it sounds confused, like the author doesn't understand the domain. (Or maybe I'm not using the terms in the standard way?) >Researchers Svetlana Bryzgalova, Anna Pavlova, and Taisiya Sikorskaya found that retail options investors lost over $1 billion during a bull market from November 2019 to June 2021. Their calculations don’t include their estimated $4.13 billion spent on the trading costs, i.e. wide bid-ask spreads that incur immediate losses for options traders. And lastly, we can’t forget the $800 million burned in that time period on commissions. Wide bid-ask spreads are a trading cost? That incurs an immediate loss? That's independent of the loss quoted in the return? If you (for some reason) do your options trading by only accepting standing bids/asks (market orders), then yes, you get a bad price ... but that would be rolled into the return figures, not an independent loss. No matter what the bid/ask spread, you can place an order in the middle and wait for a fill. And commissions aren't a "trading cost" but something that goes in a different (non-trading-cost) bucket?