Fixed dollar risk: simpler, but it doesn't scale

The simpler cousin

Fixed dollar risk is the simpler cousin of fixed fractional sizing. The rule: you risk the same dollar amount on every trade, period. Decide once that you'll risk $5 per trade on your $500 account, and that $5 stays the same whether your account is $480 next week or $560 the week after.

Why some traders prefer it. First, mental simplicity. You don't recompute risk against a moving balance every trade. Second, on very small accounts, fractional sizing can ask you to risk amounts smaller than your platform allows. $500 at 0.5% risk is $2.50. If your broker's minimum trade size means even a tight stop costs more than $2.50, the formula breaks. Fixed dollar risk side-steps that by letting you pick a number that fits the platform's minimums.

Here's the catch. Fixed dollar risk is the opposite of what you want during a drawdown. Say you start at $500 risking $5 — that's 1% per trade. After a losing streak you drop to $400. You're still risking $5, but now $5 is 1.25% of your account. As your equity falls, your effective risk percentage rises. The same trade that felt prudent at $500 feels heavier at $400, and the math agrees with the feeling.

The reverse problem hurts you too. Grow your account from $500 to $1,000, and your $5 risk is now only 0.5%. Your position size hasn't kept pace with your account, so your absolute returns plateau. Recap: fixed dollar risk is acceptable as a starter when your account is too small for fractional math to compute cleanly. Treat it as scaffolding, and graduate to fixed fractional as soon as you can.