Lets assume one retail buys at 2018.00, where Hft is serving liquidity. After that buy, due to payment for order flow a big firm knows the retail just bought (i.eg. citadel) and comes to buy lower 2017.75, ....2017.50,.. 2017.25... consuming all that liquidity at that levels and droping down the price accumulating hoping to sell in an upper average later. In this case, the first buyer is in a big loss.
Is that possible?
Is that possible?