Tiny Gaps Between One-Minute Candles in a Continuous Market

[Shadow Trader]

Foreign exchange trades around the clock during the week, yet one-minute charts often show a candle opening at a different price from the previous close. These small gaps surprise traders who expect continuity.

The explanation lies in how bars are constructed. Many platforms build charts from bid quotes. A bar closes on the last bid received, and the next bar opens on the first bid of the new minute. If the market moved between those two updates, the difference appears as a gap, even though trading never stopped. Thin sessions show this more because updates are sparse.

Some platforms force the open to equal the previous close, which hides the gap instead of removing it. Others leave the raw values. Consequently, gap counts and gap-fade rules differ across data sources.

A scalper testing a rule built on filling gaps should be aware that most of these gaps are products of sampling and are entirely ordinary. They are also close in size to the spread and may not be tradable at all, since a buy executes at the ask while the chart shows the bid. Larger intraday gaps, around news or illiquid moments, deserve separate treatment.