Session Gap Research
Study adjusted opening gaps, same-session fills and open-to-close behavior. Missing and incompatible evidence stays unavailable.
A gap is the distance between a session's opening price and the previous session's close, as a percentage. Prices are adjusted, so a dividend or a split never masquerades as a gap.
A gap is filled when price traded back through that previous close during the same session — the session's high or low crossed it. Filling three days later does not count here, because a rule that allows unlimited time is a rule that always eventually fills.
- Knowing how a listing opens. Some habitually give back their opening move; others open away and keep going.
- Judging an open in progress. Whether today's 1.2% opening move is unusual for this listing or an ordinary morning.
- Separating repricing from noise. Gaps that stayed open and ran are where the market re-rated something.
- Testing a claim. "Gaps always fill" is checkable against this listing's own record, at a threshold you choose.
It is a count over a small sample, not a probability. A 68% rate on 22 gaps is 15 events — a handful of different sessions moves it several points, and the page withholds summary rates below five qualifying gaps for that reason.
Past fills say nothing about the next open. They also say nothing about what happened between the open and the fill, which is where the risk of acting on a fill rule actually lives.
Historical gap-fill frequency is descriptive evidence, not a forecast, probability, signal, or recommendation.