Robinhood, the cryptocurrency application that caters to millennials, is selling the trades of it's members to high frequency trading firms.
This was reported a month ago and verified by Bloomberg last week.
Since then, Robinhood updated it's "How Robinhood Makes Money Page". Vlad Tenev wrote that they do send their trades to Two Sigma, Citadel, and Virtu. He claimed they are simply market makers and do not front load trades like exchanges such as the NYSE do.
Click on image to read full article.