What is ‘the tape’? Today the tape figuratively refers to the typical Time And Sales (TAS) window that plots the same concept of volume at price, colored as to whether the last trade was at Bid or Ask.
The problem with the TAS window today is that, even if you could read it, it can and does give misleading information relative to forecasting price action.
For example, a rapid series of green prints does not necessarily mean the market is going up and one should buy. Instead the prints could all be at the same price and the professionals are absorbing all the hits on the Ask until the market is eventually forced down.
In this case all those green prints mean sell. Therefore, in conjunction with the T&S window today’s traders typically look at a Depth Of Market (DOM) window which shows the Inside Bid and Ask.