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 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.

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.