The Tape: What Actually Traded
The tape is the running record of trades that actually executed: price, size, time and venue, in sequence. It shows what was done rather than what was offered, so a print cannot be canceled the way a resting order can. It is most useful for timing an entry, not for choosing one.
How it works
The tape is the sequential record of trades that actually executed. Each line carries a price, a size, a timestamp and usually the venue, in the order they printed. The name comes from the paper ticker tape; the modern window is labeled time and sales.
The book shows intent; the tape shows execution. An order resting in the order book can be canceled in a millisecond, and a print cannot — which is the entire reason anybody watches it.
A trade at the offer is somebody who wanted it now. At the offer the buyer paid up rather than wait; at the bid the seller did. Which side crossed the bid-ask spread is most of what a single line says.
And speed carries more than the prints themselves. Twenty trades in one second and the same twenty spread across a minute are identical in volume and nothing alike as markets.
A large print matters only against what is normal there. There is no absolute threshold: a size that is enormous in one instrument is unremarkable in another, and both shift by the hour.
Why it is harder than it was
Reading it is a skill with a very short shelf life. What a print implied about the participant behind it held while orders were large, human and sent whole. Execution technology removed all three conditions.
Most prints today are one order sliced into pieces. An execution algorithm cuts a large parent order into hundreds of small child orders, precisely so that the visible size distribution reveals nothing.
Some of it never arrives on time, or at all. Trades matched in dark pools reach the record after the fact, and a hidden order shows no size in level 2 before it fills.
The volume bar is the tape, summed and simplified. A candle’s volume figure is only its prints added together, which is why volume analysis and tape reading answer one question at two resolutions.
On a daily chart none of this survives. Aggregation keeps the total and discards the sequence, and sequence is the entire content of a tape.
In practice
And there is no tape at all across a gap. An opening gap is a price change with no executions in between, so there is nothing to read and nobody to attribute it to.
It never tells you where the stop belongs. A print is a fact about the last second; a stop loss is a decision about the next several hours.
And fast reading means fast trading, charged by the round trip. A one-cent spread plus a half-cent commission each way comes to 2 cents a share per round trip, and 50 round trips a day on 500 shares pays $500 before any skill enters.
It is the one record that cannot be canceled. Depth of market shows what is offered now and market makers may withdraw it; the tape reports only what has already happened.
Learning what normal looks like
Open a time and sales window beside one instrument and leave it there for several sessions. Do not trade from it. The first task is calibration — learning the ordinary rate, the ordinary size and the ordinary quiet of that instrument at each hour.
Normal is specific to the instrument and to the hour, and nothing substitutes for watching it. The first half hour and the last behave nothing like the middle of the day. A print you would call large at noon is unremarkable at the open, and no general rule will tell you which is which.
Only after that does a single line mean anything. Until you know the baseline, everything unusual-looking is unusual only to you. Most people skip the calibration, decide the tape is unreadable noise, and are half right — it is noise until the reader has a reference.
What the tape is not
- Not an identity. A print carries a price and a size, never a participant.
- Not an intention. The buyer crossing the spread may be opening, closing or hedging.
- Not a headcount. One firm can sit on both sides of a print, and nothing marks it.
- Not a forecast. It describes the past few seconds and claims nothing about the next.
How this connects
VWAP is the tape averaged by size. Every print’s price weighted by its size produces the session’s volume-weighted average, which is why large desks judge their fills against it.
An iceberg order often appears here first. Repeated prints at one price while the displayed size in the book never shrinks is the usual clue that more is resting than is shown.
High frequency trading produces a great deal of what prints. Firms quoting both sides generate a large share of the small trades, which is part of why one line says so little about any single participant.
Some bursts are routing rather than conviction. An intermarket sweep order takes liquidity at several venues in the same instant, producing a cluster of prints across prices that looks like urgency and is partly plumbing.
Payment for order flow moves much retail activity off exchange, so small orders tend to appear as off-exchange prints reported after execution.
A buying climax is the classic tape pattern in the Wyckoff tradition: a surge of prints at the ask that fails to push price any further.
And a liquidity sweep reads clearly in sequence — a fast run of prints through a level, followed by the silence that shows nobody wanted to follow it.
When it fails
In a quiet market the tape is mostly noise. Inside a trading range prints arrive in both directions at similar size and the reader supplies the pattern. Short bursts in one direction appear and fade constantly, and each one looks like the start of something.
- When the instrument is thin. A handful of prints a minute means one participant can produce everything you are reading.
- When size is being worked. An algorithm filling a parent order looks exactly like broad participation, by design.
- When the fill is passive. A resting buyer taken at the bid registers as selling pressure, because the seller was the side that crossed.
- When the venue reports late. Off-exchange prints arrive out of sequence, so the order on your screen is not the order that happened.
- When the horizon is wrong. Nothing here informs a position held for weeks; scalping is the horizon on which the attention pays.
- When you are already positioned. Every print then reads as confirmation, and the window turns into a machine for justifying the trade you hold.
The original data
“Tape reading” or “reading the tape” appears in five video titles at a median of 66,816 views. The romantic name is the one that gets watched; the functional name, time and sales, is the one to know.
That is a fact about how the subject is sold, not about how it works. Reading prints is fast trading, and fast trading multiplies the round trip: a cost that is trivial once becomes the largest line in the account at a few hundred trades a month. Use the tape to decide how you enter, not whether you enter.
Related
Order flow is the subject this page is a slice of — the tape is its execution record, and the phrase carries 110 videos at a median of 22,195 views.
Level 2 is the other half of the screen, showing resting orders rather than completed ones, across 9 titles at a median of 127,639 views.
Volume analysis is the same information aggregated, and the neighboring phrase “volume profile” runs to 228 videos at a median of 13,034.
I do not keep a time and sales window open before I have decided on a trade. Something is always happening on it, stillness starts to feel like a mistake, and the result is simply trading more. I open it once the decision is made and I am looking for a moment to get filled.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.