It's the same loss percentage for stocks day trading. The loses do not come mainly from the zero sum/fees, they come from the lack of alpha.
> Depending on the source, only around 3% to 20% of day traders make money. But that 20% estimate probably has as much to do with the time period studied—the dotcom bubble. It's hard to know for sure, but it's probably fair to say that up to 95% of day traders lose money.
https://www.investopedia.com/articles/active-trading/053115/...
> same loss percentage for stocks day trading
The Investoperia article cites three sources for that claim, the second which claims one third [1].
One fifth to one third is more in line with what I expected. It’s also a range materially higher than 5%. Broadly speaking, you’ll see 90/10 to 95/5 in zero-sum markets like FX and derivatives, and 80/20 to 70/30 for capital markets.
[1] https://www.tandfonline.com/doi/abs/10.2469/faj.v59.n6.2578?...