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Read the tape in five minutes.

BigTape shows you the unusually large trades on the stocks and ETFs you follow. This guide takes about five minutes. Every example runs on sample data, so try each one as you go.

Step 1 of 8

A print is one trade

Every time shares change hands, the trade gets reported. Each report is called a print, and it carries a price, a size and a time. Most prints are small. BigTape picks out the unusually large ones and puts them on the chart as marks, at the time and price they traded.

Sample chart. Each mark is one large trade. Select a mark to read about it.

Step 2 of 8

Two numbers tell you how big

Size alone can mislead. A $40 million trade is routine in the biggest companies and huge in a small one. So every big print gets two numbers. The first is its size in dollars. The second is its rank among that ticker's own trades since 2016.

Ranks are all-time for this ticker, since 2016. The ranks have names. A Top 0.1% print is bigger than 99.9% of the ticker's trades since 2016, with a $50,000 minimum. Top 100 and Top 10 are among its 100 or 10 largest trades since 2016. The #1 Print is its largest since 2016. Ranks compare a ticker only with itself, so a Top 10 print in a small company can be far fewer dollars than one in a giant. Prints outside the all-time top 100 show without a rank number.

The chart draws the best-ranked prints in the part of the chart you're looking at. The Prints control starts at Show 10; pick Show 5, Show 20, Show 50 or Show 100. Zoom or pan and the chart picks again for the new span.

Size ladder. Drag the slider and watch the print climb the rungs. The dollar amounts belong to this ticker alone.

Step 3 of 8

Read the marks

Every print on the chart is one of four types: Lit or Dark, regular or Sweep. Shape is the kind of trade. Every regular print is a circle and every Sweep is a diamond. Color is where it traded: one color for Lit, another for Dark. Size and number are the rank: bigger marks rank higher, every mark in the all-time top 100 carries its rank number, and the #1 Print is the biggest mark, with 1 inside.

That is the whole key. Tap any mark to see its plain name and what else is known about it. The chart's four Prints switches, Lit, Dark, Regular and Sweep, show or hide each venue and each kind, so two taps leave only the Dark Sweeps.

Mark key. Tap a type to show only that type on the chart.

Step 4 of 8

Lit or Dark

Lit trades happen on a public stock exchange, where waiting orders show before the trade. Dark trades happen off-exchange, at a private venue or inside a broker. Dark trading is normal and gets reported like any other trade. The name only means it happened away from a public exchange.

Every trade has a buyer and a seller, and the report doesn't say which side started it. So BigTape never gives a print a direction. You get what traded, how much, where and when.

One sample print drawn both ways: as a Lit print and as a Dark print. Same size and shape, different color.

Step 5 of 8

Dark Levels

When a lot of Dark dollar volume trades in one price zone, the chart shades it as a Dark Level. Each level counts its Dark dollars since 2016 and has an all-time rank for its ticker, #1 the heaviest. Ranks go to 100; smaller levels show without a rank, such as “Dark Level · $1.20B”.

The chart draws the best-ranked levels in the price range you're looking at. The Levels control starts at Show 3; pick Off, Show 5, Show 10 or Show 20. Only the #1 carries its label; point at another line to see its rank. Pan to an older span and a different set appears.

BigTape can also alert you about a level. A Revisit alert fires when price comes back to a ranked level, and a Level Break alert when price moves clearly through a level ranked #1 to #20 on heavy volume. They are alerts, not marks on the chart. A level records where trading happened. It doesn't predict where price goes.

Sample Dark Levels. Pick how many show, or pan to an older span to see a different set.

Step 6 of 8

What the tooltip adds

Some prints carry a fact worth knowing, and the tooltip says it in words. The mark stays one of the four types. A Late Report was published late and out of order. A Recurring Block is a Dark size that keeps repeating; the print card says how many prints make up the series. A Ghost Print was priced outside the day's high and low, and the tooltip says how far. Extended Hours prints traded before 9:30 a.m. or after 4:00 p.m. Eastern, on shaded time when the Extended Hours switch is on.

When large Dark trades bunch together in price and time, that is a Order Cluster. It is an alert you can set, not a mark: the prints in it draw as ordinary Dark marks.

A sample Recurring Block. Its mark is an ordinary Dark print; the tags and the sentence carry the fact.

Step 7 of 8

Check how fresh the data is

Look for the chip at the top of every screen. It tells you the state of the data and the time of the last update.

Right now it reads Delayed 15 min. Each print shows up at least 15 minutes after the trade happened.

If updates stop, it reads Stale and shows when they stopped. On a quiet day, it reads No unusual activity. In this guide it also says SAMPLE DATA, because every trade here is generated for practice.

Data states. Pick one, or tap the chip to step through them.

Step 8 of 8

Make it yours

Tap the star on any chart to add it to your favorites. Each one stays beside the chart with today's change and the all-time rank of its last ranked print. Set an alert, like a New #1 Print on any favorite, and each alert opens the chart at the moment it fired. Alerts can arrive late or not at all, so the chart is always the record. Come back after a break and Since you last looked lists what changed, biggest first.

On a computer, press N and P to step through prints. On a phone, tap any mark.

Add a sample favorite, then set a sample alert.

Reference

What each kind of print tells you

Every mark and zone on the chart, the facts a tooltip adds and the alerts about them, with what each is and what it can and cannot tell you. None of them says which side started a trade or where price goes next. Ranks are all-time for this ticker, since 2016.

The four print types

Lit regular
What it is One trade on a public stock exchange. A circle in the Lit color.
What it tells you, and what it doesn't Where it traded and how big it was. Not who started it, or why.
Dark regular
What it is One trade off-exchange, at a private venue or inside a broker. A circle in the Dark color.
What it tells you, and what it doesn't It traded away from an exchange. The public report doesn't say which side started it.
Lit Sweep
What it is Specially flagged trades landing on two or more venues within 5 milliseconds, reported by an exchange. A diamond in the Lit color.
What it tells you, and what it doesn't Trades on several venues at once. Not which side, and not why.
Dark Sweep
What it is A Sweep reported off-exchange. A diamond in the Dark color.
What it tells you, and what it doesn't One order filled on several venues at once, reported off-exchange. Not which side, and not why.

How big it was

#1 Print
What it is This ticker's largest single trade since 2016. The biggest mark, with 1 inside.
What it tells you, and what it doesn't How big the trade is against this ticker's own history. Never whether it matters.
Top 10
What it is One of this ticker's 10 largest trades since 2016. Its rank number sits inside the mark.
What it tells you, and what it doesn't Its size against this ticker's own history. Never whether it matters.
Top 100
What it is One of this ticker's 100 largest trades since 2016. A smaller mark, with its rank number inside.
What it tells you, and what it doesn't Its size against this ticker's own history. Never whether it matters.
Top 0.1%
What it is Bigger than 99.9% of this ticker's trades since 2016; $50,000 minimum.
What it tells you, and what it doesn't Unusual in size for this ticker since 2016. Not a direction, and not a reason to act.

Extended Hours
What it is A trade before 9:30 a.m. or after 4:00 p.m. Eastern, on shaded time when the Extended Hours switch is on.
What it tells you, and what it doesn't When it traded. Fewer trades happen then, so one size can stand out more.
Late Report
What it is A trade published late and out of order. Drawn as an ordinary mark; the tooltip says Late Report.
What it tells you, and what it doesn't Its time is when it was reported, not necessarily when it happened.
Recurring Block
What it is A large off-exchange trade that keeps repeating at nearly the same dollar size. The tooltip names it.
What it tells you, and what it doesn't A repeating negotiated size. Not who is behind it, or what comes next.
Ghost Print
What it is A trade priced outside that day's regular-hours high and low. Drawn as an ordinary mark at its real price; the tooltip says how far outside it sits.
What it tells you, and what it doesn't Usually how the trade was arranged, not where the market was.

Levels

Dark Level
What it is A price zone where heavy Dark dollars built up since 2016. Ranks are all-time for this ticker, since 2016; ranks go to 100, and smaller levels show without a rank.
What it tells you, and what it doesn't Where Dark trading happened. Not where price goes next.

Alerts, not marks

Order Cluster
What it is Several large Dark trades close together in price and time. An alert with their total; the prints draw as ordinary Dark marks.
What it tells you, and what it doesn't Large Dark trades gathered in one zone. Not who traded them, or why.
Revisit
What it is Price comes back to a ranked Dark Level. An alert, not a mark.
What it tells you, and what it doesn't Price returned to a zone of heavy past trading. Not that the zone will hold.
Level Break
What it is Price moves clearly through a Dark Level ranked #1 to #20 on heavy volume. An alert, not a mark.
What it tells you, and what it doesn't Price crossed the zone on heavy volume. Not that it will keep going.

What BigTape leaves to you

BigTape shows facts about trades. It doesn't say who started a trade, why it happened or what happens next. It never tells you what to trade. Those decisions are yours.

Open the demo Open the glossary

Data, not advice.