Open Types

What are Open Types?

Open types are the Market Profile taxonomy for how a session begins, popularized by Dalton's auction-theory work. Four classic types are named. Open-drive: price drives hard directionally from the first prints and does not trade back through the open. Open-test-drive: the market first probes a nearby reference or the other side of the open, finds no business, then drives away in the opposite direction. Open-rejection-reverse: an initial move runs, gets rejected, and price comes back through the open. Open-auction: price rotates quietly around the open with no early conviction.

The taxonomy comes from the Market Profile lineage: J. Peter Steidlmayer's work at the Chicago Board of Trade in the 1980s reframed each session as an auction, and James Dalton's Mind Over Markets (1990) codified the opening classifications traders still use. Dalton argued the open is uniquely informative because overnight inventory, news, and institutional participation collide in the first minutes, telegraphing other-timeframe intent before any structure exists.

The types are ranked by the confidence they imply. A drive signals strong other-timeframe participation from the bell, and the open itself then serves as a reference that should not be revisited while the premise holds. An open-auction, especially inside the prior day's value area, implies balance and a rotational session. Classifying the open early gives a working hypothesis for the day type long before the profile is complete.

Open type is half the read; open location is the other half. The framework also grades where a session opens relative to the prior day: inside value, outside value but inside range, or outside the range entirely. A drive from beyond yesterday's range must find acceptance or snap back, unlike the same drive from the middle of value. With relative volume to gauge participation, type and location turn the labels into a usable morning hypothesis.

How to identify open types on a chart

Classification happens on a 1- to 5-minute chart in the first 30 to 60 minutes, against references prepared before the bell.

1. 1Before the open, mark the prior day's high and low, its value area and point of control, and the overnight range.
2. 2A persistent move away from the opening print that never trades back through it is an open-drive; the stronger the opening volume spike, the more trustworthy the label.
3. 3A probe to one side that finds no business, then reverses through the open with conviction, is an open-test-drive; the rejected probe becomes a strong reference extreme.
4. 4An early directional run that gets rejected and trades back through the open is an open-rejection-reverse, downgrading the day toward two-sided trade.
5. 5Quiet rotation on both sides of the open, most often inside the prior day's value, is an open-auction, arguing for a responsive, rotational session.
6. 6Give the label half an hour to firm up and check it against volume delta and session VWAP: conviction opens hold one side of VWAP, auctions straddle it.

How traders use it

• As an early day-type handicap: drive and test-drive opens raise the odds of directional, elongated sessions, while an open-auction inside prior value points toward rotation between known references.
• As a risk anchor: on conviction opens, trading back through the open price voids the premise, so the open doubles as a natural invalidation line alongside the initial balance extremes.
• As confluence with continuation behavior: a drive open that then starts one-timeframing is the textbook trend-day profile, while a drive that stalls and rotates warns the label was wrong.
• As half of the open-location matrix: an out-of-range open plus a drive is the strongest continuation read, while an out-of-range open that stalls sets up the snap-back toward old value.
• As an execution filter: on drive opens traders favor pullbacks toward an anchored VWAP set at the open rather than fading strength, while open-auction sessions favor responsive trades at the edges of the developing volume profile.

Open types vs related concepts