Data study · 9 min read
What Time Do Small-Cap Gappers Hit Their High of Day?
A look at 671 US stock gap-ups of 20% or more from July 1 to October 2, 2026: when the 4:00 a.m.–8:00 p.m. ET high printed, split by gap size, price and how the day ended.
Day traders often say a gapper “tops out early”. We checked that against FennEdge’s own archive. We took every US common stock or ADR that opened at least 20% above its prior close over 66 trading sessions. For each one we recorded the first minute it printed its high of day.
Short answer: in this sample the high usually came early, and often before the opening bell.
- 53.1% of the highs printed in premarket (04:00–09:29 ET).
- 70.2% printed before 10:00 a.m., counting premarket.
- The median time of the high was 09:16 ET, 14 minutes before the open.
- 8.2% printed in after-hours trading (16:00–19:59).
There are two catches. “High of day” here covers the whole extended session from 4:00 a.m. to 8:00 p.m. And the way the day ended matters far more than gap size. Details below.
What we measured
Universe. For each session from July 1 to October 2, 2026, we took every security in the FennEdge Top Gappers archive that met three conditions:
- classified as common stock or a common-stock ADR on that date;
- an opening gap of at least +20%, where gap = (regular-session open ÷ previous close − 1);
- both the open and the previous close at $0.10 or higher.
We applied no volume minimum. That differs from the public Top Gappers list, which by default requires 1 million shares of full-day volume (see the volume breakdown below). Prices are split-adjusted daily aggregates.
High of day (HOD). This is the highest 1-minute high from 04:00 to 19:59 ET, so premarket and after-hours trading are included. If the same high printed in more than one minute, we used the first one. That happened for 78 of the 671 observations (11.6%).
Sample. The archive held 676 qualifying observations. We excluded 5 where the minute data and daily data plainly disagreed in price scale: one extended high was below the daily open, and four were more than 10× the open and close (a split-adjustment mismatch). That leaves 671 observations, 461 distinct tickers and 66 sessions, with a median of 9.5 per session. The median gap was +36.0%. Every planned session had complete coverage, and none of the 66 was an early-close day.
Buckets (ET; start of each range included, end excluded):
| Bucket | Clock range |
|---|---|
| Early premarket | 04:00–07:59 |
| Late premarket | 08:00–09:29 |
| Opening 5 minutes | 09:30–09:34 |
| Rest of first half hour | 09:35–09:59 |
| 10 o’clock hour | 10:00–10:59 |
| 11 o’clock hour | 11:00–11:59 |
| Midday and afternoon | 12:00–15:59 |
| After hours | 16:00–19:59 |
Result 1: The overall distribution
| HOD bucket (ET) | Count | Share |
|---|---|---|
| Premarket 04:00–07:59 | 245 | 36.5% |
| Premarket 08:00–09:29 | 111 | 16.5% |
| Open 09:30–09:34 | 51 | 7.6% |
| 09:35–09:59 | 64 | 9.5% |
| 10:00–10:59 | 67 | 10.0% |
| 11:00–11:59 | 28 | 4.2% |
| 12:00–15:59 | 50 | 7.5% |
| After hours 16:00–19:59 | 55 | 8.2% |
| Total | 671 | 100% |
Median HOD time: 09:16 ET.
- Premarket
- Regular session
- After hours
- Cumulative share
Show chart data
| Bin start (ET) | Session | Count | Share | Cumulative |
|---|---|---|---|---|
| 04:00 | Premarket | 96 | 14.3% | 14.3% |
| 04:15 | Premarket | 15 | 2.2% | 16.5% |
| 04:30 | Premarket | 12 | 1.8% | 18.3% |
| 04:45 | Premarket | 9 | 1.3% | 19.7% |
| 05:00 | Premarket | 7 | 1.0% | 20.7% |
| 05:15 | Premarket | 14 | 2.1% | 22.8% |
| 05:30 | Premarket | 5 | 0.7% | 23.5% |
| 05:45 | Premarket | 2 | 0.3% | 23.8% |
| 06:00 | Premarket | 7 | 1.0% | 24.9% |
| 06:15 | Premarket | 8 | 1.2% | 26.1% |
| 06:30 | Premarket | 6 | 0.9% | 27.0% |
| 06:45 | Premarket | 4 | 0.6% | 27.6% |
| 07:00 | Premarket | 19 | 2.8% | 30.4% |
| 07:15 | Premarket | 11 | 1.6% | 32.0% |
| 07:30 | Premarket | 19 | 2.8% | 34.9% |
| 07:45 | Premarket | 11 | 1.6% | 36.5% |
| 08:00 | Premarket | 19 | 2.8% | 39.3% |
| 08:15 | Premarket | 10 | 1.5% | 40.8% |
| 08:30 | Premarket | 18 | 2.7% | 43.5% |
| 08:45 | Premarket | 14 | 2.1% | 45.6% |
| 09:00 | Premarket | 27 | 4.0% | 49.6% |
| 09:15 | Premarket | 23 | 3.4% | 53.1% |
| 09:30 | Regular session | 81 | 12.1% | 65.1% |
| 09:45 | Regular session | 34 | 5.1% | 70.2% |
| 10:00 | Regular session | 30 | 4.5% | 74.7% |
| 10:15 | Regular session | 20 | 3.0% | 77.6% |
| 10:30 | Regular session | 8 | 1.2% | 78.8% |
| 10:45 | Regular session | 9 | 1.3% | 80.2% |
| 11:00 | Regular session | 7 | 1.0% | 81.2% |
| 11:15 | Regular session | 10 | 1.5% | 82.7% |
| 11:30 | Regular session | 4 | 0.6% | 83.3% |
| 11:45 | Regular session | 7 | 1.0% | 84.4% |
| 12:00 | Regular session | 3 | 0.4% | 84.8% |
| 12:15 | Regular session | 4 | 0.6% | 85.4% |
| 12:30 | Regular session | 7 | 1.0% | 86.4% |
| 12:45 | Regular session | 6 | 0.9% | 87.3% |
| 13:00 | Regular session | 3 | 0.4% | 87.8% |
| 13:15 | Regular session | 2 | 0.3% | 88.1% |
| 13:30 | Regular session | 0 | 0.0% | 88.1% |
| 13:45 | Regular session | 3 | 0.4% | 88.5% |
| 14:00 | Regular session | 3 | 0.4% | 89.0% |
| 14:15 | Regular session | 3 | 0.4% | 89.4% |
| 14:30 | Regular session | 3 | 0.4% | 89.9% |
| 14:45 | Regular session | 1 | 0.1% | 90.0% |
| 15:00 | Regular session | 0 | 0.0% | 90.0% |
| 15:15 | Regular session | 2 | 0.3% | 90.3% |
| 15:30 | Regular session | 5 | 0.7% | 91.1% |
| 15:45 | Regular session | 5 | 0.7% | 91.8% |
| 16:00 | After hours | 9 | 1.3% | 93.1% |
| 16:15 | After hours | 10 | 1.5% | 94.6% |
| 16:30 | After hours | 6 | 0.9% | 95.5% |
| 16:45 | After hours | 3 | 0.4% | 96.0% |
| 17:00 | After hours | 4 | 0.6% | 96.6% |
| 17:15 | After hours | 7 | 1.0% | 97.6% |
| 17:30 | After hours | 3 | 0.4% | 98.1% |
| 17:45 | After hours | 6 | 0.9% | 99.0% |
| 18:00 | After hours | 1 | 0.1% | 99.1% |
| 18:15 | After hours | 0 | 0.0% | 99.1% |
| 18:30 | After hours | 1 | 0.1% | 99.3% |
| 18:45 | After hours | 1 | 0.1% | 99.4% |
| 19:00 | After hours | 0 | 0.0% | 99.4% |
| 19:15 | After hours | 1 | 0.1% | 99.6% |
| 19:30 | After hours | 0 | 0.0% | 99.6% |
| 19:45 | After hours | 3 | 0.4% | 100.0% |
The early-premarket bucket is lumpy. 132 highs (19.7%) printed in the 4 o’clock hour, and 37 (5.5%) in the very first minute, 04:00. After that, the 5 and 6 o’clock hours were quiet (28 and 25). Activity picked up again from 7:00 (60), 8:00 (61) and 09:00–09:29 (50). This fits a familiar pattern: news released overnight or around 7:00–8:00 a.m. drives an early spike, and the regular session never trades above it.
Just 21 highs (3.1%) printed in the 09:30 minute itself. “Highs at the open” is mostly a premarket event in this data, not an opening-print event.
When the high came in the regular session (n = 260), the median was 10:06 ET. That is the median among names whose full extended-session high happened to print between 09:30 and 15:59. It is not the median regular-session high for every gapper; see the caveats.
Result 2: Gap size barely changes the timing
| Opening gap | n | Median HOD | Premarket | Before 10:00 (incl. premarket) | 12:00 or later | After hours |
|---|---|---|---|---|---|---|
| 20–50% | 459 | 09:25 | 52.3% | 70.4% | 16.3% | 8.3% |
| 50–100% | 129 | 08:46 | 57.4% | 70.5% | 14.7% | 7.0% |
| 100%+ | 83 | 09:26 | 50.6% | 68.7% | 13.3% | 9.6% |
- 04:00–07:59 Early premarket
- 08:00–09:29 Late premarket
- 09:30–09:34 Opening 5 minutes
- 09:35–09:59 Rest of first half hour
- 10:00–10:59 10 o’clock hour
- 11:00–11:59 11 o’clock hour
- 12:00–15:59 Midday and afternoon
- 16:00–19:59 After hours
Show chart data
| HOD bucket (ET) | 20–50% gap (n = 459) | 50–100% gap (n = 129) | 100%+ gap (n = 83) |
|---|---|---|---|
| 04:00–07:59 Early premarket | 37.7% (173) | 36.4% (47) | 30.1% (25) |
| 08:00–09:29 Late premarket | 14.6% (67) | 20.9% (27) | 20.5% (17) |
| 09:30–09:34 Opening 5 minutes | 9.2% (42) | 4.7% (6) | 3.6% (3) |
| 09:35–09:59 Rest of first half hour | 8.9% (41) | 8.5% (11) | 14.5% (12) |
| 10:00–10:59 10 o’clock hour | 8.7% (40) | 11.6% (15) | 14.5% (12) |
| 11:00–11:59 11 o’clock hour | 4.6% (21) | 3.1% (4) | 3.6% (3) |
| 12:00–15:59 Midday and afternoon | 8.1% (37) | 7.8% (10) | 3.6% (3) |
| 16:00–19:59 After hours | 8.3% (38) | 7.0% (9) | 9.6% (8) |
About 70% of highs came before 10:00 in all three gap groups. The 50–100% group has an earlier median, but its bucket shares are close to the other two. With 129 and 83 observations, we would not read much into differences of a few percentage points. Gap size alone did not separate early-high days from late-high days in this period.
Result 3: Lower-priced gappers peaked earlier
| Regular-session open | n | Median HOD | Premarket | First 30 min (09:30–09:59) | Before 10:00 | 12:00 or later |
|---|---|---|---|---|---|---|
| Under $1 | 97 | 08:29 | 61.9% | 6.2% | 68.0% | 15.5% |
| $1 to under $5 | 259 | 08:50 | 59.5% | 17.0% | 76.4% | 11.2% |
| $5 and up | 315 | 09:31 | 45.1% | 20.6% | 65.7% | 19.4% |
Sub-$5 names were more likely to print their high before the bell. Names that opened at $5 or more had more highs in the first half hour and after midday. One reading is that higher-priced gappers include more news-driven or larger-company moves that keep trading through the day. We did not test that here. The sub-$1 group has only 97 observations, and its regular-session buckets are small.
Result 4: How the day ended is the biggest split
| Close vs. open | n | Median HOD | Premarket | Before 10:00 | 12:00 or later | After hours |
|---|---|---|---|---|---|---|
| Closed at or above open | 233 | 10:25 | 28.8% | 40.3% | 37.8% | 19.7% |
| Closed below open | 438 | 08:37 | 66.0% | 86.1% | 3.9% | 2.1% |
Most gappers in the sample (65.3%) closed below their open, and their highs were heavily front-loaded. 86% had already printed their high before 10:00. Only 3.9% made it after midday.
The minority that closed at or above the open looked very different. Their median HOD was 10:25, more than a third peaked after midday, and about one in five peaked after the 4:00 p.m. close.
- 04:00–07:59 Early premarket
- 08:00–09:29 Late premarket
- 09:30–09:34 Opening 5 minutes
- 09:35–09:59 Rest of first half hour
- 10:00–10:59 10 o’clock hour
- 11:00–11:59 11 o’clock hour
- 12:00–15:59 Midday and afternoon
- 16:00–19:59 After hours
Show chart data
| HOD bucket (ET) | Closed at or above open (n = 233) | Closed below open (n = 438) |
|---|---|---|
| 04:00–07:59 Early premarket | 25.8% (60) | 42.2% (185) |
| 08:00–09:29 Late premarket | 3.0% (7) | 23.7% (104) |
| 09:30–09:34 Opening 5 minutes | 1.7% (4) | 10.7% (47) |
| 09:35–09:59 Rest of first half hour | 9.9% (23) | 9.4% (41) |
| 10:00–10:59 10 o’clock hour | 14.2% (33) | 7.8% (34) |
| 11:00–11:59 11 o’clock hour | 7.7% (18) | 2.3% (10) |
| 12:00–15:59 Midday and afternoon | 18.0% (42) | 1.8% (8) |
| 16:00–19:59 After hours | 19.7% (46) | 2.1% (9) |
This split uses information you only have after the close. You cannot know at 9:30 which group a stock will land in. Part of the result is also mechanical. If a stock closes well above its open, its high is likely to be late. If it fades from an early peak, the high is early by definition. Read this table as a description of two kinds of day, not a way to sort stocks in advance.
Two related figures:
- Of the names whose high printed in premarket, 81.2% closed below their regular-session open. Only 12.6% closed below the prior day’s close, so most kept part of the gap.
- Of the names whose high printed at 10:00 or later (n = 200), 69.5% closed at or above their open.
Across the full sample, 9.2% closed below the previous close, giving back the whole gap.
Result 5: The volume filter changes little
| Full-day volume | n | Median HOD | Premarket | Before 10:00 | After hours |
|---|---|---|---|---|---|
| 1M shares or more | 633 | 09:12 | 53.7% | 70.9% | 7.7% |
| Under 1M shares | 38 | 09:30 | 42.1% | 57.9% | 15.8% |
Applying the public list’s 1M-share filter keeps 94% of the sample and leaves the headline numbers almost unchanged. The under-1M group is too small (38) to say much. Its higher after-hours share is consistent with thin trading, where one late print can set the high.
Robustness checks
- By month. Median HOD was 09:14 in July (n = 196), 09:06 in August (n = 270) and 09:30 in September (n = 192). The premarket share was 54.6%, 56.3% and 47.9%. October has only two sessions (n = 13), so we do not report it separately.
- Possible bad prints. A 1-minute high can come from a single off-market trade. As a check, we also dropped the 15 observations whose high was more than 2.5× both the open and the close. Results barely moved: n = 656, median 09:16, 53.0% premarket, 70.6% before 10:00.
- Ties. 11.6% of observations hit the same high in more than one minute. Under a last-minute convention their times would shift later, so the shares above slightly favor early buckets.
How this compares with other public studies
Many public analyses of intraday highs and lows look at index components or broad stock universes during regular hours only. They often describe a U-shape: extremes cluster near the open and, to a lesser extent, the close.
This sample is different in three ways:
- it covers only stocks with a large opening gap;
- it counts the whole 04:00–20:00 window;
- it covers a single three-month period.
Under those conditions, the largest cluster is not 09:30 but premarket, especially the 4:00 a.m. hour and 7:00–9:29. The open-and-close shape is still faintly visible among regular-session highs (09:30–10:59 versus 12:00–15:59, then after hours). We treat this as a description of this archive, not a general law.
Caveats
- Sample period. This is one stretch of 66 sessions from July to early October 2026. Market conditions, news flow and the mix of tickers can shift these shares.
- Selection. The sample is defined by an opening gap of 20% or more using the official regular-session open, which is known only at 9:30. It is not a premarket scanner reconstruction. Stocks that ran in premarket but opened below +20% are excluded.
- Extended-hours high. Premarket and after-hours trading is thinner, and a premarket high can be set by small volume. For names whose extended high printed outside regular hours, this study does not report when their regular-session high occurred.
- 1-minute resolution and first-high convention. Times are the start of the first 1-minute bar at the high. Two highs a few seconds apart in different minutes are separated, and ties go to the earliest minute.
- Data quality. Minute highs can include isolated off-market prints. We removed 5 clear price-scale mismatches and ran a 2.5× sensitivity check, but a few odd prints may remain. Prices are split-adjusted, and adjustments can be revised later.
- Survivorship. Security type comes from reference data as of each historical session, not from today’s active list. Tickers that were later delisted, renamed or reverse-split stay in the sample. This reduces survivorship bias but does not remove every classification error.
- Repeat tickers. 461 tickers produced 671 observations. Multi-day runners count once per session.
- No float or catalyst controls. We did not condition on float, news type, dilution filings or market-wide moves. Those are natural next cuts.
Methodology summary
- Gap = regular-session open ÷ previous session close − 1.
- Day change = close ÷ previous close − 1.
- Volume is full-day consolidated volume, not premarket volume.
- HOD = the first 1-minute bar holding the highest high from 04:00 to 19:59 ET.
- Universe: common stock and common-stock ADRs with an opening gap of +20% or more, open and previous close at least $0.10, 2026-07-01 to 2026-10-02.
- Exclusions: 5 price-scale mismatches.
- Medians: for an even count, the average of the two middle minutes, rounded to the minute.
- Data as of: 2026-10-02; archive snapshot read 2026-10-05.
- These are retrospective daily and minute aggregates, not real-time data.
Related reading
Browse the historical samples by trading day in the Top Gappers Calendar, and see when those stocks reached their daily highs in the Gapper HOD Timeline. For the concepts behind this study, read gap up and gap down, premarket, regular and after-hours sessions, volume and relative volume and researching why a stock moved, or look up terms in the glossary.
This article explains common concepts; examples are not trading recommendations.
