Yeah you're right...but on to the monoply thing....INCA own part of ARCA, all of ISLD, is part of the Reuters Group, owns LJR, Protrader Group LP, and investments in others.
They try to maintain a very neutral approach to what they do through their research depts, etc....but look at their connections...research, trading, clearing, news (reuters), IPOs (an investment they have in Hambrecht), and other ECNs.
Talk about empire building through acquisition... If you cant beat em, buy em. (ISLD)