Sometimes called Level II data, depth-of-book refers to the full robustness of an order book. It's a comprehensive view of all trading activity, providing every quote on the book so that you can ...

The data – which is comprised of all order activity in the Nasdaq system - can be aggregated either by price level or by MPID. Orders received into Nasdaq’s book are immediately visible on ...

In retrospect, the exchange experienced only "a sharp but brief disruption in volumes and order book depth," with key market metrics showing robust recovery within weeks of the incident.