Who this entry is for — Anyone who wants to describe how a session range develops relative to the Initial Balance using the taxonomy in the original CBOT manual.
Primary source: Chicago Board of Trade, CBOT Market Profile®, Part I: Reading the Market Profile Graphic, 1996, pp. 14–21.
The four categories describe how the range develops relative to the Initial Balance: they are not operational signals or standalone forecasts for the next session.
Prerequisites
Initial Balance, Equilibrium and imbalance, and Market Profile.
The four CBOT day types
In plain language — The question is: how much of the final range was already inside the Initial Balance, and in which directions did the market extend it?
| Original type | Criterion described in the guide | Descriptive reading |
|---|---|---|
| Normal | The IB contains about 85% or more of the range; extension is absent or slight | Balance |
| Normal Variation | One-sided extension, from a few ticks to about twice the IB | Balance → imbalance → new balance |
| Trend | One-directional movement and close at the directional extreme; extension considerably beyond twice the IB | Imbalance |
| Neutral | Range extension above and below the IB | Limited net influence or uncertainty |
The percentages and ratios describe the historical CBOT futures examined in the guide. They are not universal probabilities and may require documented adaptation for different instruments and sessions.
Normal day
In plain language — The initial range contains almost the entire day. The market rotates within parameters established early, with no extension or only a limited one.
In the CBOT guide, a Normal day has about 85% or more of its final range inside the Initial Balance. Any range extension tends to be slight.
This describes the session geometry; it does not automatically prescribe buying the low or selling the high.
Normal Variation day
In plain language — The Initial Balance does not contain the whole auction: the range extends on one side and establishes a new parameter.
A Normal Variation day has range extension in one direction. In the manual, the extension may run from a few ticks to about twice the Initial Balance; the wider the extension, the more influence the guide attributes to longer-timeframe participants.
Limit — “Up to twice” is a descriptive threshold in the historical model, not a statistical boundary. Row size, trading hours, and product structure can change the comparison.
Trend day
In plain language — The range keeps extending in the same direction and the session closes near the directional extreme.
The guide calls it a Trend day when the market moves predominantly in one direction, closes at the directional extreme, and develops range extension considerably greater than twice the Initial Balance.
The definition comes from the behaviour of the full session. It should not be inferred from a letter shape alone or merely from an open outside the previous Value Area.
Neutral day
In plain language — The range extends in both directions. The two extensions reduce the net influence attributable to either side.
A Neutral day has range extension both above and below the Initial Balance. In the guide's language it indicates uncertainty and may accompany a change, but it does not determine the next direction by itself.
Reproducible observations
| Field | What to record |
|---|---|
| Initial Balance | Times and width |
| Final range | Width and share contained in the IB |
| Range extension | Direction, size, and timing |
| Close | Position within the range |
| Configuration | Session, tick aggregation, and data used |
D-, P-, and b-shaped profiles are conventions common in later literature, but they are not automatic synonyms for Normal, Normal Variation, Trend, and Neutral. Using them requires a separate source and definition.
Common error — Turning an ex-post classification into an intraday strategy supposedly confirmed at the open. The type develops during the session and can be assigned with certainty only after observing that development.
Summary card
- Normal: almost the whole range is inside the IB.
- Normal Variation: extension on one side.
- Trend: strong one-directional extension and close at the extreme.
- Neutral: extension in both directions.
Sources
- Chicago Board of Trade, CBOT Market Profile®, Part I: Reading the Market Profile Graphic, 1996, pp. 14–16 — Normal, Normal Variation, Trend, and Neutral through Initial Balance and range extension.
- Chicago Board of Trade, same work, pp. 20–21 — relationship between balance, imbalance, and range development.