[jmrobertson]

Yes, not shady, but it totally unravels the argument concerning HFTs helping price discovery. I know the "hey retirement and index funds are doing it, think of the pensioners!" argument is common defense of it, but that's not at all the target audience of DPs. It's liquidity going off exchange, which hurts price discovery, simple as that. Considering how competent trade execution/slippage capabilities are for the types of broker-dealers that would be handling index/ret/pension volumes, that argument is nonsense

[atemerev]

Well, dark pools are a counter-HFT measure, of course they have limited price discovery. If you want price discovery, you can go to lit markets. If you want matching without showing your orders, you can put orders to the lit book algorithmically, or go to a dark pool. It's not that there is no choice. And people traded off-exchange like forever, OTC market still exists and predates exchanges.