Many beginner traders believe that finding a high-win-rate strategy is the secret to profitability. In reality, you could have a strategy that wins 70% of the time, but if you do not understand position sizing, a short string of losses will quickly blow up your account.
Professional risk management is built around a single question: How much money am I risking if this trade stops out?
The golden standard of risk management is the 1% Rule. Here is how to calculate it and apply it to every Opening Range Breakout (ORB) trade you take.
1. What is the 1% Rule?
The 1% Rule states that you should never risk more than 1% of your total account equity on a single trade.
- Important Clarification: Risking 1% of your account does not mean you only buy shares worth 1% of your account. It means that if the stock hits your stop loss, your realized financial loss is exactly 1% of your total capital.
- Example: If you have a $10,000 trading account, your maximum allowed risk per trade is $100. If the trade fails, your account balance drops to $9,900.
By capping your risk at 1%, you would need to lose 10 consecutive trades in a row to lose just 10% of your account. This math ensures your survival during unavoidable market drawdowns.
2. The Position Sizing Formula
To figure out how many shares of a stock to buy, you must calculate your position size using this simple formula:
$$\text{Share Size} = \frac{\text{Account Dollar Risk}}{\text{Entry Price} - \text{Stop Loss Price}}$$
Which simplifies to:
$$\text{Share Size} = \frac{\text{Account Dollar Risk}}{\text{Stop Distance}}$$
3. Step-by-Step Position Sizing Example
Let’s walk through an ORB breakout setup on a stock:
- Your Trading Account: $10,000
- Allowed Dollar Risk (1%): $100
- Breakout Entry Price (ORH Close): $150.00
- Your Selected Stop Loss Level: $148.00
Step 1: Calculate the Stop Distance
Subtract your Stop Loss from your Entry Price: $$$150.00 - $148.00 = $2.00 \text{ per share}$$
Step 2: Divide Dollar Risk by Stop Distance
Divide your maximum dollar risk ($100) by the stop distance ($2.00): $$\frac{$100}{$2.00} = 50 \text{ shares}$$
The Result:
You will buy 50 shares of the stock at $150.00.
- Total capital allocated to purchase these shares is $7,500 (50 shares * $150.00).
- If the stock drops to $148.00 and triggers your stop loss, you sell your 50 shares, losing $2.00 per share.
- Your total loss is $100 (50 shares * $2.00), which is exactly 1% of your $10,000 account.
4. Why This Protects You Against Leverage
Many day traders use 4x margin leverage to buy massive position sizes. However, buying too many shares compresses your stop distance. If you buy 1,000 shares of a $150 stock ($150,000 position) on a $10,000 account, a minor fluctuation of just $0.10 will cost you $100. You will be stopped out by normal market noise before the strategy even has a chance to play out.
By calculating your share size based on your stop distance, your risk is always constant. Whether your stop distance is $0.50 or $5.00, your loss is always capped at $100. This discipline is what separates professional, consistent traders from gamblers.