The article is a bit confusing. There's "PFOF" which is basically middle-man profit taking. That's not particularly shocking unless it's egregiously delayed. Bu

The article is a bit confusing. There's "PFOF" which is basically middle-man profit taking. That's not particularly shocking unless it's egregiously delayed. But then there's selling data to high frequency traders. This sentence in the article conflates these two very different things... > As we saw above, Robinhood’s main revenue source comes from selling customer trade data to other firms. This is a controversial practice known as “Payment for Order Flow” (PFOF in financial regulatory lingo). I am not getting this? Is it the case that ordering stock shares from a market maker like Citadel is identically selling data to high frequency traders? FWIW, I admit I don't _really_ understand how market transactions work, and I definitely don't feel alone!