TSLA same-day gap-fill rates by gap size and direction (last ~3 years)
The old market proverb that "all gaps get filled" doesn't square with TSLA's intraday behavior. Looking at 751 regular-session days over the last ~3 years, small opening gaps under 1% filled same-day about 84.2% of the time and typically did so almost immediately (median time-to-fill = 1 minute), while very large gaps over 3% filled only about 19.1%. The overall same-day fill rate across the sample was 63.2%.
Below you'll find the full study: minute-bar filtering to US RTH, the gap definition, bucketed results by absolute gap size and direction, counts, and time-to-fill distributions. The numbers show a clear small-vs-large contrast; the intermediate buckets and the largest gaps are noisier, and the detailed charts and tables beneath explain where the signal is strongest.
For TSLA over the past ~3 years, when the stock opens with a gap from the prior close, how often does price trade back to the prior close ('fill the gap') within that same session, and does the fill rate depend on the gap's size and direction? Thesis: small gaps (<1%) fill the large majority of the time but big gaps (>3%) rarely fill same-day, debunking the blanket trader adage that 'all gaps get filled.
How this was measured
Filtered TSLA minute bars to US regular session (Mon–Fri, 09:30–16:00 ET) and restricted to the last ~3 years of data. For each session with a valid prior close, computed the opening gap as (09:30 open − prior RTH close)/prior close. A same-day 'fill' occurs if any intraday minute's range enveloped the prior close (low≤prior_close≤high). Time-to-fill is measured in minutes from the first 09:30 bar to the first such touch. Results are bucketed by absolute gap size (<1%, 1–2%, 2–3%, >3%) and split by direction (gap up vs gap down). Analysis window: 2023-06-01 to 2026-05-29 (based on available RTH minute data).
The key numbers
Reading the numbers
Across 751 TSLA sessions with an opening gap, the prior close was touched intraday in about 63.25% of cases. Small gaps under 1% filled most of the time (~84.21%) while gaps larger than 3% filled only about 19.12%.
The charts
This bar chart breaks same-day fill rates into four gap-size buckets for gap-ups and gap-downs. The eye goes to the leftmost bars: <1% gaps fill very often (about 86.19% for gap-ups and 81.76% for gap-downs), while the rightmost >3% bars are near 19% for both directions (19.35% up, 18.92% down). The decline in fill rate as gap size grows — and the small difference between up and down — supports the thesis that small gaps mostly get filled same day, but big gaps rarely do.
This plot shows how long it takes to first touch the prior close on days that actually filled, with counts, min/max and means for each bucket and direction. For filled <1% gaps many touches happen immediately (min 0), the median time for <1% fills is 1 minute (headline), and the means are about 18.48 minutes for gap-ups (n=181) and 14.91 minutes for gap-downs (n=139). As gap size grows the typical time-to-fill increases (means ≈53.93 min for gap-up 1–2% n=67; ≈98–122 min for 2–3% buckets; ≈76–132 min for >3%), but note the >3% filled cases are few (n=6–7) so those averages are noisy.
Gap-fill summary by direction and gap size
| direction | gap_bin | n_gap_days | fill_rate | median_time_to_fill_min | p90_time_to_fill_min |
|---|---|---|---|---|---|
| Gap Up | <1% | 210 | 0.8619 | 2 | 34 |
| Gap Up | 1–2% | 121 | 0.5537 | 27 | 155.2 |
| Gap Up | 2–3% | 50 | 0.34 | 57 | 194.6 |
| Gap Up | >3% | 31 | 0.1935 | 131.5 | 207.5 |
| Gap Down | <1% | 170 | 0.8176 | 1 | 21.4 |
| Gap Down | 1–2% | 91 | 0.4725 | 11 | 121.4 |
| Gap Down | 2–3% | 41 | 0.3659 | 86 | 248.6 |
| Gap Down | >3% | 37 | 0.1892 | 52 | 140.2 |
The takeaway
Short answer: small opening gaps under 1% almost always fill same-day, while very large gaps over 3% rarely do. Specifically, gaps <1% filled about 84.21% of the time versus only about 19.12% for gaps >3%, and the overall same-day fill rate across the sample was 63.2% from 751 sessions. Direction nudges the odds — for example gap-ups <1% filled ~86.19% while gap-downs <1% filled ~81.76%. The fill rate falls steadily with gap size: 1–2% gaps filled about 55.37% (n=121) and 2–3% gaps about 34% (n=50), so the middle buckets are much more mixed. When small gaps do fill they happen fast — the median time-to-fill for filled <1% gaps was 1 minute. Overall confidence: the small-vs-large contrast is a clear, real pattern in this 751-day sample; the intermediate buckets are a weaker signal and the very largest-gap bins should be treated as noisy.
The fine print
- Detection uses minute bars; sub-minute touches between bars can be missed.
- This counts only regular trading hours; pre-market or after-hours fills are excluded.
- Largest-gap bins are thin (e.g., 31 gap-up days >3%), so those specific rates are noisy.