Core terms
Opening range breakout (ORB)
Trader usage for price trading beyond the high or low of the session's first minutes (the opening range). Results depend on the range length, whether premarket prices count and the trigger used.
An ORB is a family of definitions rather than one setup. Range length (1, 5, 15 or 30 minutes), session (regular session only or premarket included), trigger (a trade beyond the range or a 1-minute close beyond it) and the time window each change which days count. One workable version: the 09:30:00 to 09:34:59 ET range, triggered by the first 1-minute close above its high from 09:35 to 10:29 (Illustrative definition). On gappers a premarket-inclusive range often has a higher high, so the same bar can be a trigger under one definition and not another.
Outcomes include a break that runs, a break that fails, and a false break that drifts back inside the range. In the FennEdge Gapper HOD study, the day's high printed inside the 5-minute opening range on 51 of 671 days (7.6%; 2026-07-01 to 2026-10-02; FennEdge archive; as of 2026-10-02); these are hindsight bounds on days, not trade results.
The idea is commonly credited to futures traders of the 1980s and 1990s, notably Toby Crabel's 1990 book on short-term price patterns.
What traders should verify
Fix range length, session, trigger, stop, target and time stop before the first entry, and log days without a trigger and skipped triggers alongside the trades taken.
Do not conflate
Trader usage; there is no official definition. Results published for index futures or large caps do not transfer to small-cap gappers without a separate count, and switching definitions after seeing outcomes is a form of hindsight.
Primary source
Trader usage: there is no official definition, and platforms and tools may calculate it differently.