Profile shapes

It is 09:00 ET (21:00 ICT, winter) and you are writing the morning sheet. You open yesterday’s NQ volume profile and look at it for three seconds. Fat in the middle, or fat at one end? Is there a thin spike sticking out anywhere? You have just described the whole session: where buyers and sellers agreed to trade, and which prices they barely touched. This lesson gives you the four words for what you saw, and answers the harder question: does yesterday’s shape tell you anything about today?

Key terms

Profile shape (hình dạng hồ sơ): the outline a session’s volume profile leaves when you read its rows from top to bottom Definition. It describes where trade concentrated in a finished session.

Tail (đuôi): a run of thin rows at one extreme of the profile: prices that traded briefly and were then left Definition. A tail at the low is a buying tail; a tail at the high is a selling tail.

Chart first: a P and its tail

How it works

Four shapes

Four classic outlines cover most sessions Definition:

• D-shape (hình chữ D, balanced): fat middle, thin at both ends, POC near the centre of the range. Trade was two-sided and value formed in the middle. It is the profile a normal day (M1.04) usually leaves.
• P-shape (hình chữ P): fat top, thin stem below, often ending in a buying tail. Price travelled quickly through the lower prices and then built value near the top.
• b-shape (hình chữ b): the mirror. Fat bottom, thin stem above, often a selling tail at the top. Price travelled quickly through the upper prices and then built value near the bottom.
• Trend profile (hình dạng xu hướng): long and thin, no dominant body. Price kept moving to new prices, so volume is spread along the whole range and the POC is a weak reference. The extreme it ends on often has no tail, which M2.09 calls a poor high or low.

Shape plus POC location

Shape and POC location together give you a one-line description before you open any indicator Definition:

• Fat body, central POC: value formed in the middle; trade was two-sided.
• Fat body, POC at one end: value formed at that end, after a fast move through the other end.
• Thin throughout: one-sided travel, little agreement at any price.

Write that line on your sheet. It is what you compare today against. One caution: the shape depends on what you asked the platform to draw. Switch between the RTH session and the full Globex day, or change the row size, and the same day can turn from a D into a P. Always note which profile you read.

The tail and its extreme

A tail records prices the auction visited briefly and left Definition. Its extreme is a plain fact about yesterday: the lowest (or highest) price anyone traded. That makes it a useful line for your description. As long as today trades above a P’s tail low, “the low was visited and left” still describes the structure. If today starts building volume below it, the description is out of date and yesterday’s shape is history. Treat this as a bookkeeping rule House rule, not a claim that price turns at the tail.

Myth / hypothesis: “Tails hold when they are retested, and extremes without a tail get revisited” Lore. A public NQ study (“Order Flow, Measured”: one practitioner’s pre-registered study, Jan 2018 to Aug 2026, intervals not clustered by session, so it can never raise a claim above Plausible) tested both. Buying and selling tails held on a retest no more often than the baseline: +0.3 percentage points [−5.1, +5.7], n = 1,330. Poor highs and lows were revisited no more often than tailed extremes: +1.0 [−2.8, +4.8], n = 3,766. Both inconclusive: no edge shown, which is not the same as proven useless.

What traders read into shapes

The classic auction-market reading (Dalton, Mind Over Markets) adds a story about who traded. A P after a rally is often old shorts buying back (short covering) rather than fresh long-term buying. A b after a drop is often old longs selling out (long liquidation). D-shapes are said to favour fading both extremes, and thin trend profiles are said to get revisited because they left little trade behind. These stories are worth knowing: traders use them, and they make you ask who was trading. As forecasts, they are hypotheses.

Myth / hypothesis: “A P-shape means short covering, so buy the next session; a b-shape means long liquidation, so sell it; fade the edges of a D” Lore. The test is in the box below.

What the data says

Why it is still worth knowing

• Shared vocabulary. “Prior day was a P with a tail to 17,960” says in a few words what would otherwise take a paragraph, and profile traders read it the same way.
• Describing the auction. The shape tells you where yesterday’s agreement happened and which prices were barely traded. That is the context the rest of this module builds on.
• Framing risk. The tail extreme is a clear line where your description stops fitting. If you have a separate, tested reason for a trade, that line is a natural place to say “I was wrong about the structure.”
• A hypothesis you can test. Log every shape and what the next session did for a few months. Your own sample will be small (EV3.01 shows how wide its interval is), but you will see the base rate for yourself.

Worked example: describe yesterday, check it this morning

A synthetic NQ session shaped like the chart above: tail down to 17,960, value area 18,000–18,030, POC 18,010.

Step 1, describe (after the close). “P-shape. Fast move up through 17,960–17,995, value built 18,000–18,030, buying tail to 17,960.” That is the whole description. Note what it leaves out: it does not say buyers will defend 17,960 today.

Step 2, write the check on the morning sheet (09:00 ET, 21:00 ICT) House rule. “Prior day P; tail extreme 17,960. Above 17,960, yesterday’s description still fits. Volume building below 17,960 means yesterday’s structure is out of date.”

Step 3, watch the open.

Version A. NQ opens at 18,005, inside yesterday’s value. It dips to 17,975 twice on light volume and trades back into the body. The description still fits, and that is all it tells you. The dips holding above the tail do not make a rotation to the 18,010 POC more likely than a move from any other price; a trade still needs its own reason, written so it can be scored (M4.09).

Version B. NQ opens at 18,005, slices to 17,950, and volume builds there for the first 30 minutes. Yesterday’s description is now out of date: today’s auction is building value below the tail. Holding on to “but it was a P-shape” after that is trading a photograph of yesterday.

Neither version is a trade signal. Version A keeps yesterday’s context alive; version B retires it.

Common mistake: Trading yesterday’s shape as today’s plan: “it was a P-shape, so I buy every dip.” Shapes describe a completed auction. Today’s auction is a new negotiation that can accept, reject or ignore yesterday’s structure. The shape gives you a description and the line where it breaks (the tail extreme); the developing session decides whether it still applies.

Common mistake (evidence): Reading “inconclusive” as either “proven useless” or “still works, just unproven”. It means the test could not tell an effect from no effect at this sample size. Keep shapes as description, and do not size up because a shape looks clean.

Recap:

• Four shapes: D (value in the middle, two-sided), P (value at the top after a fast move up), b (value at the bottom after a fast move down), trend (thin, one-sided, little agreement anywhere).
• Shape plus POC location is a one-line description of a finished session; note the session and row size you used.
• A tail marks prices visited briefly and left; its extreme is the line where yesterday’s description stops fitting today.
• Trading shapes as signals was inconclusive on NQ (−0.2 pp, n = 1,779), and so was “tails hold on retest”: no edge shown.

Further reading:

• Following the Auction: Market Profile Basic Language: a plain-English vocabulary of profile shapes and auction language.
• Market Profile Course — The Nature of Markets: a structured introduction to reading Market Profile structure.
• Mind Over Markets — James Dalton: the book behind the auction-market reading of every shape in this lesson.
• Order Flow, Measured: the public practitioner study cited in this lesson (claims AP-05, AP-06, AP-11).

Prerequisite: M2.04 Composite profiles · Next: M2.06 Market Profile structure, where the same shapes appear as TPO letters · Connects to: M2.09 (poor vs tailed extremes), M1.04 (day types), M2.02 (value area)

Educational content only — not financial advice. Futures trading involves substantial risk of loss.