Quote from cohvi:
Hi,
Can someone clear the difference (if any) between:
The Book, Open Book, Level II, DOM and the Tape.
I can seem to find an exact definition to the above.
I know this are the bid ask and price volume data...
Thanx.
Everyone calls it differently. They're mostly the same thing and there's no right or wrong definition. The terminology doesn't really matter, in trading but here's my attempt:
What's a common in most of the above (except for tape) is it's a list of Bid/Ask in different prices.
1. Book. Historically, this starts with the specialists in exchanges and the floor. They had a little paper pad with a list of prices, firms, and quantity, of different sources trying to trade. As a whole, they called it the book. The specialists would then match trades based the "Specialist Book".
Long time ago, when everything was done manually. There was the human specialists making the markets. The incoming order request information (the book) was exclusive to the specialist. Because the specialists know where everyone is trying to buy and sell, this gave them the opportunity to "deal" the market. Even to this day, they would be "dealing" the incoming trade requests to create liquidity, and making money by picking up ticks, here and there.
So back in the days, "Specialist Book" was synonymous to having an edge, "insider information", "secrets/information to riches" and etc. Of course, after the NASDAQ Markets, the most of the information was offered to the public.
From this, they usually called the Bid/Ask Data with the Price, firms, and quantity, a book. So in your list, "The Book, Open Book, and Level II." would be considered the same.
2. DOM. This is more of a condensed version of the book. They only post the price and the cumulative quantity for a specific product.
3. Now, tape reading is different. It's an act of reading the tape or Time-Of-Sales. Back in the days, they printed the trade transactions on a paper tape. Most traders used the tape, to base their trades.
Now days, tape will be considered the Real-time Time-Of-Sales. Or simply, the quotes. Being able to analyze the market through the quotes would be considered tape reading. Book and charts are usually seperated from tape reading, as there are references to traders such as chart reader or book trader.
... these are off my head... I maybe inaccurate with some stuff but who really cares what people call what.