Do stocks that gap up keep rising?
No. Since 1995, US stocks on the day they opened more than half a percent above the prior close beat the same day's median stock over the next week 49.8 times in 100, and over the next month 50; a coin flip gives 50. The first week leans a fraction below chance, a faint tilt not reliable on its own; beyond it there is no measurable edge.
The paper
The full study: its data, method, robustness, limits and sources.
Opulence Alpha Research · Published Sep 25, 2026 · Data through Aug 21, 2026
Keywords: gap up, gap up stocks, do gap ups keep going, gap and go strategy, breakaway gap, opening gap·JEL classification: G11, G12, G14, C12, C58
- Universe
- The same for every study: 1,767 US common stocks in the 11 GICS sectors, 422 of them since delisted; S&P 500 members since 1996 plus large and mid-sized companies outside the index
- Period
- Every Wednesday from Jan 4, 1995 to Aug 19, 2026: 1,634 Wednesdays across 7,959 trading sessions
- Sample
- n = 1,763 stocks of the 1,767-stock universe; 1,889,758 stock-weeks, a median of 1,148 stocks per Wednesday
- Outcome
- Return over the next 1, 5, 21 and 63 trading sessions against the same day's median stock
- Inference
- t on non-overlapping dates; proven only when |t| ≥ 3 and the same sign in at least 60% of years
1Introduction
When a stock opens above the previous day's close, many traders read the gap as strength: demand too eager to wait for the open. Chart books name breakaway and runaway gaps as the start or the middle of an advance (Edwards and Magee 1948), and "gap and go" is a familiar day-trading setup. This study asks whether stocks that open with a gap up go on to beat other stocks over the following session, week, month and three months.
2Data and method
2.1Sample design
Population and frame. The population is US common stocks listed on the NYSE and Nasdaq; funds, ETFs, trusts, preferred shares, warrants and units are excluded. The sampling frame is a fixed universe of 1,767 companies, drawn once when the platform was built and not re-sampled since, in two strata. Stratum 1 is a census of the S&P 500: every company in the index at any time since 1996 whose price history could be recovered, 1,027 companies of which 413 have since delisted; it holds 76% of the index's members in 1996 and at least 96% in every year from 2010. Stratum 2 is 740 large and mid-sized companies outside the index, selected in proportion to the market's sector weights from the stocks that passed a minimum share price of $15 and a minimum average daily trading value of $25 million; 9 of them have since delisted.
Sample. The unit of observation is a stock-week: one stock on one Wednesday. A stock enters a Wednesday's cross-section when it has a valid close that day, a value of the signal and a measured outcome; bars flagged as bad data and returns that cross a change of issuer are left out. This study's sample is n = 1,763 stocks of the 1,767: 1,889,758 stock-weeks on 1,634 Wednesdays from Jan 4, 1995 to Aug 19, 2026, a median of 1,148 stocks per Wednesday (range 820 to 1,371). 331,954 stock-weeks (17.6%) come from the 422 companies that have since delisted. Every stock and every Wednesday carries equal weight.
Representativeness. Table 1 gives the sample by GICS sector beside the S&P Composite 1500: 7.9% of companies would have to change sector for the two to match exactly. By latest market value, 55% of the active companies are large (at least $10bn), 38% mid ($2–10bn) and 6% small. Because Stratum 2 was chosen from companies listed at construction, its history carries survivorship bias. Section 4 reads the result horizon by horizon and year by year.
Companies in this study's sample, of them those since delisted, the size of the active companies, the sample's share of stock-weeks and the sector's share of the S&P Composite 1500.
| Sector | Sample | Delisted | Large | Mid | Small | Stock-weeks | S&P 1500 |
|---|---|---|---|---|---|---|---|
| Information Technology | 282 | 67 | 122 | 76 | 18 | 13.9% | 12.7% |
| Financials | 256 | 60 | 114 | 74 | 8 | 14.6% | 17.2% |
| Industrials | 255 | 53 | 126 | 67 | 11 | 15.9% | 17.5% |
| Health Care | 237 | 47 | 92 | 81 | 16 | 12.4% | 10.9% |
| Consumer Discretionary | 209 | 39 | 69 | 87 | 12 | 12.3% | 12.9% |
| Energy | 105 | 30 | 39 | 31 | 5 | 5.9% | 4.7% |
| Consumer Staples | 101 | 38 | 40 | 17 | 5 | 5.9% | 4.9% |
| Materials | 94 | 34 | 35 | 24 | 2 | 5.6% | 5.1% |
| Real Estate | 84 | 10 | 40 | 32 | 2 | 5.7% | 6.9% |
| Communication Services | 80 | 31 | 28 | 13 | 5 | 3.9% | 3.3% |
| Utilities | 60 | 13 | 35 | 12 | 0 | 4% | 4% |
| All sectors | 1,763 | 422 | 740 | 514 | 84 | 100% | 100% |
Sample: n = 1,763 of the 1,767 companies. Size by latest market value for the 1,338 active companies with one: large ≥ $10bn, mid $2–10bn, small < $2bn. S&P 1500 shares count the constituents of the S&P 500, MidCap 400 and SmallCap 600 (1,506 companies, lists read Sep 25, 2026). Sectors are each company's current GICS sector.
2.2Signals
| Signal | Definition | Since | Wednesdays |
|---|---|---|---|
| Gap up | The stock opens more than 0.5% above the previous close, counted on the day it happens | Jan 4, 1995 | 1,633 |
2.3Measurement
Outcome. The return from the close on the Wednesday to the close 1, 5, 21 and 63 trading sessions later, on closes adjusted for splits and dividends, compared with the same day's median stock; half of all stocks beat the median by construction, so chance is 50 in 100 on every date. No delisting return is added.
Each Wednesday, the stocks showing the reading are scored against the same day's median stock. A state counts on every Wednesday it holds; a cross or breakout counts only on the Wednesday it happens.
The t-statistic uses non-overlapping dates only. A result is called proven when |t| is at least 3, it held in at least 60% of years and it is large enough to matter; with 1,470 tests across the studies, a looser bar would pass dozens by luck.
Full data and methods3Results
Figure 1 reads every horizon. Stocks that opened with a gap up beat the median stock 49.4 times in 100 over the next session, 49.8 over the next week, 50.0 over the next month and 50.0 over the next three months. The first two readings are faint: a tilt a fraction below 50, too small to count as an edge. The last two show no measurable edge at all.
Share of stocks showing the reading that beat the same day's median stock, by horizon. The line at 50 is chance, the grey band the range chance alone produces; a filled square is a proven relation.
Each square is one calendar year; filled = a year in which the average stock showing the signal lagged the median stock over the next week. Years are counted, not shown in order.
A signal with an edge would fill most squares, or leave most empty.
Out of every 100 stocks that opened with a gap up, 50 beat the median stock over the following week (Figure 2), across 403.4K stock-weeks. The jump at the open did not carry into a lead over other stocks in the days that followed.
A gap is the price catching up with news or orders that arrived overnight. Once the stock opens higher, that information is in the price; across hundreds of stocks, what followed was an ordinary week, which is what these numbers show.
4Robustness
Table 3 reads the gap up horizon by horizon. Over the next session the rate was below 50 in 25 of 32 years: a steady tilt, but too small to count as an edge. Over the next week it was below 50 in 18 of 32 years, and over the next month above 50 in 16 of 32, close to an even split.
Share that beat the median stock, its t-statistic on non-overlapping dates, and the years in which it pointed the same way.
| Horizon | Beat the median | t | Years, same way |
|---|---|---|---|
| Gap up, session | 49.4 | -4.8 | 25 / 32 |
| Gap up, week | 49.8 | -3.2 | 18 / 32 |
| Gap up, month | 50.0 | -1.0 | 16 / 32 |
| Gap up, three months | 50.0 | -0.6 | 19 / 32 |
5Limitations
- Every opening gap of more than half a percent counts the same: the study does not separate large gaps from small ones, gaps on earnings or other news from gaps without it, or gaps that closed during the day from gaps that held.
- A gap is counted only when it happens on a Wednesday, the day the studies observe; gaps on other days are not in the sample.
- Before costs. Averages exclude trading costs, taxes and market impact.
- Same-close timing. Returns start at the close the signal is computed from; a real trade would start later.
- Survivors among smaller companies. The non-index names were chosen from companies listed when the universe was built; no delisting returns are added.
6Conclusion
A gap up records what happened overnight. Measured on the day against the same day's median stock, stocks that opened with a gap up did not go on to beat other stocks: a faint tilt a fraction below a coin flip over the first week, and no measurable edge over the month or three months that followed. The jump at the open describes news the price has already absorbed, not a forecast of the move to come.
References
- Edwards, R. D. and Magee, J. (1948). Technical Analysis of Stock Trends.
- Park, C.-H. and Irwin, S. H. (2007). What Do We Know About the Profitability of Technical Analysis? Journal of Economic Surveys 21(4).
- Benjamini, Y. and Hochberg, Y. (1995). Controlling the False Discovery Rate: A Practical and Powerful Approach to Multiple Testing. Journal of the Royal Statistical Society, Series B 57(1).
- Grinold, R. C. and Kahn, R. N. (2000). Active Portfolio Management, 2nd ed. McGraw-Hill.
- Harvey, C. R., Liu, Y. and Zhu, H. (2016). … and the Cross-Section of Expected Returns. Review of Financial Studies 29(1).
- Shumway, T. (1997). The Delisting Bias in CRSP Data. Journal of Finance 52(1).
Appendix A. Questions readers ask
- Do stocks that gap up keep going up?
- Not measurably. Since 1995, US stocks that opened more than half a percent above the previous close beat the same day's median stock over the next week 49.8 times in 100, and over the next month 50 times, against 50 for a coin flip.
- Is a gap up a bullish sign?
- Not in the data. Over the session after a gap up, those stocks beat the median stock 49 times in 100: a fraction below a coin flip, a faint tilt that is not reliable on its own.
- Why doesn't a gap up predict further gains?
- A gap is the price catching up with news or orders that arrived overnight. Once the stock opens higher, that information is in the price; across hundreds of stocks, what followed was an ordinary week, which is what these numbers show.
- How was the gap up measured?
- Every Wednesday from Jan 4, 1995 to Aug 19, 2026, the stocks that opened more than half a percent above the previous close that day were compared with the same day's median stock over the next 1, 5, 21 and 63 trading sessions, on the same universe of 1,767 US stocks every study uses.
Data availability and citation
Every figure in this paper is quoted from one frozen snapshot, published as JSON with the sample description, the robustness results and the test counts. The same snapshot feeds the research console, so the two cannot disagree.
Opulence Alpha Research (2026). Do stocks that gap up keep rising? Opulence Alpha Studies, Sep 25, 2026. https://opulencealpha.ai/studies/gap-up
Research, not advice. A measured tendency across hundreds of stocks is a nudge for any one of them, never a forecast of its price.