Opening range breakout (ORB): the day traders' strategy, and the math behind it

Opening Range Breakout (ORB) is a day trading strategy: you mark the high and low of the first minutes after the market opens (15, 30 or 60 minutes), and buy when the price breaks the high, usually after it has pulled back to test it (retest) and continued. The stop is tight, below the test candle; the target is a multiple of the risk; and everything closes before the end of the day. It's a method with real logic, research that partially supports it, and math that most people promoting it don't show you.

We did not backtest ORB ourselves: it requires years of minute-level data, which we don't have. So this page does something else: it breaks down the common rules, calculates what must happen for them to be profitable after costs, and states explicitly what this requires of you.

The common rules

• Opening range: The high and low of the first 30 minutes (09:30 to 10:00 New York time, 16:30 to 17:00 Israel time in summer). No trade before the range closes.
• Filters: A liquid stock with volume Relative volume (at least 2x normal for that time of day), a moderate opening gap, a tight bid-ask spread, and no earnings report or news that day. The index (e.g. QQQ) above its VWAP, meaning the broad market is supportive.
• Breakout and retest: A 5-minute candle that closed above the range high on high volume; afterward the price returns to the breakout area, stays above it and above the VWAP, and only a break of the test candle's high is the trigger. Chasing a long candle is not allowed.
• Stop and exits: Stop below the low of the test candle, usually 0.25% to 1% from the entry. Sell half at 1R, move the stop to breakeven, sell the rest at 2R. A time-stop at midday and full closure before 16:00.
• Limits: Small risk per trade (a quarter of a percent), at most two trades per day, stop trading after two losses.

The math the ads don't show

In the common exit structure, the maximum profit on a trade is 1.5R: half the position is sold at 1R and half at 2R. A trade that reached 1R and then returned to breakeven yields 0.5R. A trade that stopped out loses 1R. Assume a reasonable distribution:

• Breakeven requires more than half of trades to reach 1R before the stop is hit. For an intraday breakout with a half-percent stop this isn't a given — it's an optimistic assumption.
• Costs are measured against the stop, not against the price. A round-trip spread and slippage of 0.1% to 0.15% amount to 15% to 50% of the risk unit when the stop is 0.25% to 1%. In swing trading with a 5% stop, the same costs are 2% of the R. That's the structural difference between the two.
• The research is cautious. Studies on opening range breakouts have found positive results in certain samples, mainly during volatile periods, and emphasized that the findings depend on liquidity and costs. Broad research on day traders found that the vast majority lose money over time, and a very small group profits consistently.

What this requires of you, in practice

ORB is not a system you run in the background. Entries between 17:05 and 19:00 Israel time, a time-stop at 20:00, closing by 22:45, every trading day, in front of the screen, with Stop-limit orders typed within seconds and real-time minute data. This is a second job, during evening hours, measured in tenths of a percent.

Anyone considering this seriously needs to go through the protocol of Strategy testing: pre-set closed rules, testing on minute data with costs double the estimate, at least two hundred trades, and then a hundred trades in simulated trading with documentation of every slippage. Only afterward real money, and at a risk of a tenth of a percent per trade.