Three is the limit. If I need more, I close one and get the OB for another. A little anoying... nitro
True, but that's an understatement! Many of the best traders don't look at it, even when they have access to it. It can actually screw you up and shake you/scare you out of good positions, as well as get you to rely on bad positions because of false orders or long cleared out orders that aren't updated (or, like the tape, not showing the real size orders on the floor and only showing what the spec wants people to see).
I used to totally believe that.....but my eyes have COMPLETELY been opened to the power of openbook lately. Yeah it has a 10 second delay and yes, it is worth little in the larger vol stocks where the action is in the crowd but the book even with the 10 second delay actually LEADS the regular level II a lot of the time in the other 1000's of stocks as you will see size come in on open book way before the specialist shows it if it comes in right before the update. EX. stock has been selling off and is 1X1 40.05 by 40:10 or whaever NYSE. Open book updates and you have 5K to buy at 40.08 and there is an ecn at 40.06 still trying to get short. Without the book you can't buy the ecn shares with any confidence because if the stock has been comming in the next print might be down another dime, here you can buy the ecn and the next print is likely 10 cents up not 10 more down. Sometimes you will see the above where the specialist is putting together a print or finishing up someone in the crowd and an electronic limit order comes in and the book actually leads by a few despite the update....then eventually when the 1X1 goes away you see the specialist displaying what you knew 3 seconds earlier. While some firms continue to talk down open book, other niches of traders have embraced it and could not trade effectively without it. As far as it screwing you up, yeah bids and offers can get pulled but how often are daytraders putting up 10-20K share fake bids and offers. Not often, atleast not that I have met. Also if you trade off the bid size ask size as most high vol traders tend to the book is almost mandatory these days as the big bids and offers are almost always pennied rapidly these days to cover up real size. Having the book allows you to feel more confident the size is still there. Bottom line: It won't help you in IBM or JPM maybe but it is a huge tool in lower volume stocks. As soon as they roll out that liquidity quote every firm will have to have open book anyway so you might as well get to used to using it now IMO.
So that means a total of three can be open at one time, but in order to open another one, you must close one of the three first. Thanks