If you have subscribed to Level 2 Advance (Nasdaq TotalView), you are able to view the level 2 market by order data. Market by Order (MBO) displays the “full depth” of bids/offers on the Nasdaq order book, which includes all US exchange listed securities.
Market by Order (MBO) can help you track order flows. You can see the market participant information (MPID) of bid and ask orders. This way, you can see which exchange supplies the liquidity.
What is MPID?
MPID is the Market Participant Identifier used to report trades. This is a 4 character alpha code. The Clearing Firms will be reporting INSITE data by MPID.
You can view all the valid MPIDs published by FINRA.