Read the website on these guys and seems their specialty is secrecy, at least they have been on the buy side lately. They come up as house 14

http://www.itg.com/about/

These fellows seem to specialize in putting together small trades into larger crossable blocks for institutional investors. I noticed them the first time last week, however I have no feel for how active they have been. they are house 13

http://www.instinet.com/pdf/news/BLX_Launch_.pdf

With Anonomys and Jitney and now ITG and Instinet, it is pretty tough for the retail investor to get any feel for the tapes as to what is going on. No wonder Goldman Sachs is desperate to get their software back.