Is it now common practice for HFT market-making algorithms to post liquidity in dark pools and exchanges at the same time?
I ask because I have been reading some documentation (https://squeezemetrics.com/monitor/docs#dpi) on a service which is claiming that market-maker inventory is affected by dark pool buying/selling activity (and that this then affects exchange quotes/prices).
Yet last I heard about this in the news people were getting freaked out about letting HFT into dark pools and fining people or something.