I found the statement below on the Esignal web site. Does anybody know is this 10 second delay exists on all NYSE open books or is the esignal book a lagger to the others.
Thanks.
How Often Data for NYSE Open Book Updates
The NYSE sends out the data in 10-second bursts. That's why you may see the Open Book out of sync occasionally with the best bid/ask quote in a quote window. Unlike with NASDAQ Level II data, the NYSE doesn't stream the data tick by tick in Open Book