for those that trade NYSE, what do you put more epmhasis on? The openbook or level2? I know that in level2, it shows limit orders and market limit orders. I would often see huge sizes, sometimes at round numbers and I am guessing that's an institutional market limit order. What does that mean? Did he give that order to the specialist to work or did the institutional buyer/seller tries to handle the stock himself? Why would the huge size show up in the openbook? My guess is that the seller/buyer is almost done and just wants to use a market limit order to complete the fill. They would often appear more on the offer side than the bid side and that further leads me to the conclusion that if they are using market limit orders, they are almost finished with the order and had to absolutely sell the last batch...Most of these big sizes are not at whole numbers (700, 1000, etc...) but rather odd numbers such as (564, 453, 243)... What does that mean when the huge size is not at round numbers? Could that be an institutional order or is just a large trader?