"you could start out asking about disguising/hiding liquidity across sigma x or instinet etc." That's interesting. I always wondered how massive volume sometimes doesn't move a stock...so I just searched on your terms.... It'd be awesome to have access to "dark pools" of liquidity. That's a big leap for a day trader. "hedging using riskless principal trades" That's something my TOS account hasn't exposed me to. Still searching for more on that... Thanks for your insights.