The Nifty traded outside its first 15-minute range on all 64 sessions I checked, between 3 July and 1 October 2026. The first break was downward on 39 days. But a break was a poor guide to the close: only 31 of the 64 days ended beyond the side that broke first.
This is the data behind a question I kept skipping past when I tested 25 versions of an opening range breakout. Before asking whether a breakout makes money, it helps to know how the raw market behaves around the opening range. Everything below is a count of days, not a forecast.
The question and the data
The question. After the first 15 minutes, how often does the Nifty trade above or below that range, which side goes first, when, and where does the day close compared with the range?
The data. One-minute bars for the Nifty 50 index from my own market log. The study covers 64 sessions, from 3 July to 1 October 2026. Daily closes come from the same log, and I checked the latest one, 22,421.95 on 1 October, against Zerodha Kite.
Some limits I found when I looked closely:
- 63 sessions have all 15 opening bars. On 6 August one opening minute is missing, so that day's range is built from 14 bars.
- 64 days is a small sample. One or two days moving between groups can change a percentage by a few points.
- The whole period was a falling market. The Nifty closed at 24,271.20 on 3 July and at 22,421.95 on 1 October, a fall of 1,849.25 points (7.62%). A sample like that will lean toward downside breaks, and I wouldn't expect the same split in a rising quarter.
How I counted
The opening range is the highest high and lowest low of the bars from 9:15 to 9:29. There is no exchange definition, and 15 minutes is a common choice, so I used that. I did not tune it.
A break is the first bar from 9:30 onward whose high is above the range high (an up break) or whose low is below the range low (a down break). If both sides were broken during the day, the first break is the one that came first. There were no days when both sides broke in the same minute.
Then I sorted each day by where the official close landed:
- Beyond: past the side that broke first (above the range high after an up break, below the range low after a down break)
- Inside: back between the range high and low
- Opposite: past the other side of the range
Results: every day broke, and down came first more often
| First break | Days | Share |
|---|---|---|
| Down | 39 | 61% |
| Up | 25 | 39% |
| No break all day | 0 | 0% |
Every session broke the range at least once. That surprised me less once I saw the widths: the range averaged 75.9 points, while the full day's range averaged 170.1 points over the same 64 days. On an average day, the first 15 minutes covered about half (49.4%) of the day's eventual high-to-low distance, which leaves a lot of room to go past it.
The 39 to 25 split toward down breaks matches the falling market of those three months. It is a description of the sample, not something I'd expect to repeat.
Where the day closed after the first break
| First break | Closed beyond | Closed back inside | Closed beyond the other side |
|---|---|---|---|
| Down (39 days) | 19 (49%) | 16 (41%) | 4 (10%) |
| Up (25 days) | 12 (48%) | 6 (24%) | 7 (28%) |
| All (64 days) | 31 (48%) | 22 (34%) | 11 (17%) |
This is the number I care about most. A first break was followed by a close in the same direction on 31 days and by something else on 33. It was close to a coin flip.
The two directions failed in different ways. After a down break, the most common alternative was a drift back into the range (16 days). After an up break, 7 of 25 days went on to close below the range low, compared with 4 of 39 the other way round. In a quarter when the index fell 7.62%, upside breaks were the ones more likely to reverse fully. With 25 up-break days, that is a few days of difference, so I hold it loosely.
Both sides broken. On 29 of the 64 days (45%), the Nifty traded through both the range high and the range low at some point. Even on days that closed beyond the first break, the path was often not one-way.
A recent example: on 1 October the opening range was 22,508.35 to 22,589.05, a width of 80.7 points. The Nifty broke above it at 10:01, broke below it at 12:10, and closed at 22,421.95, beyond the opposite side. That day goes in the "up, then closed beyond the other side" cell.
When the first break came
| Time of first break | Days | Share |
|---|---|---|
| 9:30 to 9:34 | 35 | 55% |
| 9:35 to 9:59 | 14 | 22% |
| 10:00 to 10:59 | 14 | 22% |
| 11:00 or later | 1 | 2% |
More than half the first breaks came within five minutes of the range closing, and 49 of 64 (77%) came before 10 AM. The one late day was 3 July, when the range held until a down break at 1:33 PM.
The early breaks fit what I found when I looked at when the Nifty makes its high and low of the day: the first hour is when most of the day's extremes get set, so a range that covers only 15 minutes is usually tested quickly.
Did the width of the range matter?
I split the days into three groups by opening-range width.
| Opening range width | Days | Closed beyond | Back inside | Other side |
|---|---|---|---|---|
| Under 60 points | 18 | 8 (44%) | 7 | 3 |
| 60 to 90 points | 30 | 15 (50%) | 8 | 7 |
| 90 points or more | 16 | 8 (50%) | 7 | 1 |
Not much. Narrow ranges closed beyond the first break slightly less often, but the difference is one or two days. The widest group had only one full reversal, which is what you'd expect: the wider the range, the further the index has to travel to close past the far side. The widest range in the sample was 174.45 points on 28 September and the narrowest was 36.1 points on 24 August.
I also looked at the 13 weekly and monthly expiry days in the sample. Eight of them (62%) closed beyond the first break, compared with 23 of the other 51 days (45%). Thirteen days is too few to say anything firm, but it fits the more directional closes I described in what changes on expiry days.
Limitations
- One quarter, one trend. The sample is three months of a falling market. The direction split, and possibly the reversal pattern, depend on that.
- One definition. A 5-minute or 30-minute range would give different counts. I picked 15 minutes in advance and haven't tested the others, so I can't tell you how sensitive the results are.
- Touch, not hold. A single minute bar printing one tick past the range counts as a break. A rule that needs a candle close beyond the range would count fewer breaks and fewer two-sided days.
- Index, not a tradeable price. These are Nifty 50 spot bars. Futures and options add premium, spread and costs that this count ignores.
- My own log. I haven't compared the minute bars with exchange files. Daily closes match Kite where I checked.
What I take from it
The first break is not the news it looks like on a chart. In this sample the Nifty always left the opening range, usually within minutes, and then closed in that direction about half the time. If I were designing anything around the opening range, I would start from those base rates: 48% closed beyond the first break, 34% closed back inside, 17% closed past the other side.
It also explains something from my 25-version test. Versions that won a lot of trades could still end up flat, because the days that didn't follow through were common, not rare. If you're building your own test, the backtesting guide covers how I set up the data, and the daily range and India VIX study shows how much the day's range itself varies.
I'll rerun the count once the sample includes a rising stretch, and I'll report the direction split separately for up and down months.
Sources
- Nifty 50 one-minute bars and daily closes: my own market log, 3 July to 1 October 2026 (aggregate counts only)
- Cross-check of the 1 October close: Zerodha Kite market data
This post describes an analysis of the sessions I analysed, for information only. It is not investment advice or a recommendation to trade. Past patterns say nothing certain about the future. I am not registered with SEBI as an investment adviser or research analyst.