High of Day Breakout: 274 SPY Sessions, Counted by the Hour
A high of day breakout is an intraday move in which price trades above the highest price the session has reached so far, after that high has stood for a while. Day traders watch it as a sign that buyers have absorbed the selling at the day's top and the move may extend.
Every session has a running high, the highest price traded so far. When price comes back up to it after a pullback and trades through, day traders call it a high of day breakout. This page defines the move exactly, walks through one on SPY’s 5-minute chart on 25 September 2026, and counts every case on SPY’s hourly bars since October 2023.
How it forms
The session sets a high, then backs off. Often the high comes early, in the first busy hour. Price pulls back, sometimes for minutes, sometimes for hours, while the old high sits overhead.
Then price returns and trades through it. The reasoning traders give is that orders wait above a visible high, from short sellers protecting positions and from buyers who want proof of strength first, and that filling them at once can carry price further. That is the idea being tested below, not a measured fact.
The standing time is what separates a breakout from a trend. In a steady climb every bar makes a new high, and none of them is a breakout of anything. The setup traders mean is a high that held, then gave way.
It differs from its neighbors by the level it uses. An opening range breakout uses a range fixed by a set time after the open. A previous day high break uses yesterday’s level. The high of day moves all session, so the level being broken can be set at 10:00 or at 2:00.
The rule counted here
Hourly sample. Yahoo Finance 1-hour bars for SPY, 27 October 2023 to 25 September 2026, regular hours only, US Eastern time with daylight saving applied bar by bar. Seven half days and the zero-volume bars Yahoo adds to them were dropped, leaving 723 full sessions of seven bars each (the last is the 3:30 to 4:00 half hour).
A break. An hourly bar whose high is above every earlier high of the session, where the bar that set that earlier high came at least two bars before, so at least one full hour passed with no new high. The first such bar in each session is counted. In practice the earliest possible break is the 11:30 bar.
Outcomes. Whether the official daily close finished above the broken high; whether any later hourly bar traded back below it; and how far the day’s high went beyond it. The official close is used because it differed by more than 2 cents from the last hourly bar’s close on 521 of the 723 sessions.
A limit worth knowing. The hourly bars reached the daily bar’s high and low within 2 cents on 668 of 723 sessions. On the rest the daily bar holds a print the hourly bars do not, up to $4.01 away, so every level here comes from the hourly bars alone.
A worked example
Friday 25 September 2026, on 5-minute bars. SPY opened at $768.78 and set a high of $770.31 in the 9:55 bar. It then fell to $766.29 by 10:15 and spent the next two hours under the old high.
The 12:00 bar broke it. Its high was $771.44, $1.13 above the level, and the next two bars pushed on to $771.98. At 12:20, a bar traded down to $769.99, back below $770.31, so a trader holding from the break saw the position under water within 20 minutes.
The close still finished above the level. SPY closed the day at $771.35, $1.04 above the broken high, and the day’s high of $772.28 came in the 3:50 bar. The break was followed by a higher close and a higher high, and still included a trip back through the level.
The original data
274 of the 723 hourly sessions had a high of day breakout, 37.9%. 61 came in the 11:30 bar, 67 at 12:30, 57 at 1:30, 47 at 2:30 and 42 in the last half hour.
At the close, the result was close to even. 150 of the 274, 54.7%, closed above the broken high. The median close sat 0.02% above it. Breaks in the 11:30 bar closed above the level 36 times in 61 (59.0%), breaks from 12:30 to 1:30 65 times in 124 (52.4%), and breaks from 2:30 on 49 times in 89 (55.1%). For comparison, 383 of all 723 sessions, 53.0%, closed above their official open. Against an even split, 150 of 274 is within chance (exact binomial p = 0.13). Every session is in the SPY hourly breaks file.
Trips back below the level were the norm. 195 of the 274, 71.2%, had a later hourly bar trade below the broken high. The median extension, from the level to the day’s final high, was $0.89, or 0.16%.
The low side looked similar. 245 sessions broke a standing low of day by the same rule. 109 of them (44.5%) closed below the broken low, and 185 (75.5%) traded back above it later.
When the day’s high gets set
The first hour and the last half hour hold most of them. In 240 of the 723 sessions the day’s high was set in the 9:30 bar, 33.2%, and in 152 it came in the 3:30 to 4:00 half hour, 21.0%. The five hours between held 76, 52, 56, 58 and 89.
That shape matters for a midday break. A new high at 12:30 is competing with a day that most often peaks either early or at the end. The day’s low showed the same shape: 286 sessions set it in the first hour and 98 in the last half hour.
The 5-minute sample says the same, on a small scale. SPY’s 60 sessions from 2 July to 25 September 2026 held 50 breaks of a high that had stood for at least 30 minutes, timed from 10:00 to 3:25 so each had half an hour after it. 24 of the 50 (48.0%) closed above the level, 41 (82.0%) traded back below it within 30 minutes, and 48 (96.0%) did so before the close. This is one summer of one fund and it is listed in the SPY 5-minute breaks file.
When it fails
Price comes straight back. On 5-minute bars, four out of five breaks traded back under the level within half an hour. A stop placed just under the broken high sits where price went most of the time.
The break is the day’s last push. 124 SPY breaks came in the middle of the day, when the hourly count shows few session highs being set. On 59 of those 124 the close finished at or below the broken level.
The extension is small. A median of $0.89 beyond the level, on a fund priced in the hundreds, leaves little room once the spread and a pullback are paid for.
One fund, three years. The hourly figures cover 723 SPY sessions from late 2023 on, a mostly rising market, and say nothing direct about single stocks.
Related
The opening range breakout page covers the fixed-time version, where the range is set in the first minutes and does not move. Previous day high and low counts how often SPY takes out yesterday’s levels, and in which hour. And the false breakout page covers the break that reverses back through its level, which on these counts was the common path even for breaks that closed above.
Treat a break of the day’s high as a fact about where price has been, not a promise about where it goes. When I trade one, I expect price to dip back under the old high at some point, and I decide in advance how far under it can go before I am wrong.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.