The professional "active investors" generally lose money after fees are taken into account:
"When performance is measured using before-fee model alphas and compared across the cross-sectional distribution, any active fund performance advantage is substantially less than one would conclude from benchmarking to average index fund performance. Moreover, any advantage of the top active managers over the top index funds is much less than the advantage of the worst index funds over the worst active funds. When performance accounts for residual risk, active funds no longer outperform index funds. " -https://www.cambridge.org/core/services/aop-cambridge-core/c...
JOURNAL OF FINANCIAL AND QUANTITATIVE ANALYSIS Vol. 53, No. 1, Feb. 2018, pp. 33–64 COPYRIGHT 2018, MICHAEL G. FOSTER SCHOOL OF BUSINESS, UNIVERSITY OF WASHINGTON, SEATTLE, WA 98195doi:10.1017/S0022109017000904 Passive versus Active Fund Performance: Do Index Funds Have Skill? Alan D.Crane and Kevin Crotty
I'm sure there are better sources, but I'm lazy today.
Day traders get even worse:
https://mathinvestor.org/2020/07/day-trading-in-the-age-of-c...