3. One company and its price

The trade tape (TAS)

TAS (time and sales) lists every reported trade in a US stock as it prints, with time, price, shares, venue and conditions, and the VWAP of the trades seen.

  • 5 min
  • 3 questions
  • Lesson 1 of 2

Why you would care

Who is trading this right now, how much, and where? A chart shows one candle per minute. Behind it there may be 500 separate trades: tiny ones, big ones, some on exchanges, many away from them. Old traders "read the tape" to feel the market's pulse. Today it still tells you whether a move is real (many shares, many venues) or thin (a few odd lots before the open).

The idea from scratch

A print is one reported trade: a time, a price, a number of shares, a venue.

In the US, every trade must be reported within seconds to a central system, the consolidated tape. It merges all venues into one stream. Stocks are split by where they are listed:

  • Tape A

    stocks listed on the NYSE.

  • Tape B

    stocks listed on other exchanges such as NYSE Arca.

  • Tape C

    stocks listed on Nasdaq (AAPL is Tape C).

A venue is where the trade happened:

  • an exchange (Nasdaq, NYSE, Arca, BZX, EDGX, IEX...), or
  • off-exchange: trades between a broker and a large trading firm (a wholesaler), or inside a private matching system (a dark pool). They are reported through a facility run by FINRA, the brokers' regulator.

Some prints carry conditions that say they are special:

odd lot
Fewer shares than one round lot (under 100 shares for most stocks)
ext hours
Printed outside the regular session (before 9:30 or after 16:00 New York)
ISO
Intermarket sweep order: a buyer or seller hitting several venues at once, in a hurry
open / close
The opening or closing auction print
late
Reported later than the rules allow

VWAP (volume-weighted average price) is the average price of trades, where bigger trades count more. Above VWAP, the latest buyers are paying more than the average buyer today.

Diagram: Nasdaq leads to Consolidated tape; NYSE, Arca, BZX, EDGX, IEX... leads to Consolidated tape; Off-exchange: wholesalers, dark pools leads to Consolidated tape; Consolidated tape leads to TAS: one row per print; TAS: one row per print leads to VWAP and range of what was seen.
Wide diagram: scroll sideways to see all of it.

See it in Gloom

Gloom screenshot: TAS AAPL before the US open on 2026-10-06
TAS AAPL before the US open on 2026-10-06: the summary on top, then one row per trade, newest first. Free plan, so 15 minutes delayed. Historical example.

open ittype TAS AAPL. h / l switch between the Trades tab and the NBBO tab (next lesson).

  1. VWAP 332.8246 150,480 shares since 08:29:06.106: the average price of the trades loaded, and how many shares that covers.
  2. Range 332.4600 to 332.8900 last 47 pctl: the lowest and highest print seen, and where the last one sits in that range (47th percentile, in the middle).
  3. Session 331.6500 to 336.2100: the session's low and high.
  4. Rows: 08:50:21.895 332.6400 25 Nasdaq ISO · ext hours · odd lot C. Time to the millisecond, price, 25 shares, on Nasdaq, an intermarket sweep, before the open, smaller than one round lot, Tape C. Green prices ticked up from the trade before; red ticked down.
  5. Many rows say Off-exch: these trades did not happen on an exchange.
  6. The 40-share prints on Arca and BZX carry no odd lot mark, while 20- and 25-share prints do. AAPL trades above $250, so its round lot is 40 shares, not 100 (see the round-lot table in the next lesson).
  7. Footer: 15m delayed · Oct 6 08:50:21 ET snapshot. On Pro it streams in real time.

Prints of 10,000 shares or more stand out in the table: those are the trades that move markets.

Practice and recap

Try it3 tasks
  1. In the screenshot, is the latest price above or below VWAP? (Below: 332.64 vs 332.82.)
  2. Why are almost all prints odd lots? (It is premarket: few people trade, in small sizes.)
  3. Find a print of 100 shares or more. (08:49:51.865, 100 shares off-exchange.)
Common mistakes4 mistakes
  • Reading premarket prints as the "real" price. Volume is tiny; the open can be far away.
  • Assuming off-exchange means suspicious. Most retail orders are filled off-exchange by wholesalers.
  • Comparing VWAP across days: it restarts every session.
  • Forgetting the delay on the free plan when timing a trade.
Check yourself3 questions
  1. What is a print?
  2. What does odd lot mean?
  3. Which tape carries Nasdaq-listed stocks?
Answers
  1. One reported trade: time, price, size and venue.
  2. A trade of fewer shares than one round lot (100 shares for most stocks).
  3. Tape C.
Words in this lesson9 words
print
One reported trade.
consolidated tape
The single merged stream of all US trades (and best quotes).
venue
Where a trade happened: an exchange or off-exchange.
off-exchange
Trades away from exchanges: wholesalers and dark pools.
wholesaler
A large trading firm that fills brokers' customer orders.
dark pool
A private matching system that does not show its orders.
odd lot
A trade or order of fewer than 100 shares.
ISO (intermarket sweep order)
An order that hits several venues at once.
VWAP
The volume-weighted average price of trades.

Educational material about reading market data, not investment advice.