Order flow has been sold for much longer than the more recent commission-free trading trend, which was primarily driven by Robinhood. Robinhood just decided the

Order flow has been sold for much longer than the more recent commission-free trading trend, which was primarily driven by Robinhood. Robinhood just decided they'd sell order flow without also taking commission. More to the point: the primary consumer of order flow is market making HFTs, which DE Shaw is not. Stat arb/quant trading firms don't rely on market making rebates for trading profits.