system
A chat on subreddit /r/wallstreetbets
human
How do you think RH makes money? No commissions, but they gotta make money somewhere. They selling your data, homie. 
  
 If a product is free, it's because *you* are the product.

gpt
They take a negligible percent of cash. Since their model attracts more users the cut ends up being huge compared to some brokerages that charge commissions. 
  
 There also is no data to sell (that would be legal to sell). Everyone knows what Robinhood traders are doing because Robinhood displays hot activities in the app.