There are numerous papers on day-traders performances. Data paints rather dim portrait of day traders.
What I have gathered from research papers published after 2000. Too mind some of those papers used older data from 90's.
- Collectively day-traders are net-negative. Over 6 month period most traders individually are net negative.
- Around 35%-20% day-traders made money on pre 2000 data sets. For newer papers this number has drastically decreased to 5-15%
For the paper in question, quoted in article is latest. Truth is, it is getting even worse - data from 2013 to 2015 in the Brazilian equity futures market, the third in terms of volume in the world, shows that 97% of all traders who trader more than 300 days lost money. So 3% (or 1551 individuals) made money.
Only 17 individuals (1.1% of 1,551) earned more than the Brazilian
minimum wage (US$ 16 per day), only eight individuals (0.5% of 1,551) earned more than
the initial salary of a bank teller (US$ 54 per day), and the individual who earned the most
earned US$ 310 per day on average.9 Moreover, the eight individuals who earned more than
the initial salary of a bank teller did so with great volatility: the standard deviation of the
daily prot of these eight individuals ranged from US$ 632 to US$ 3,308.