The maximum number of contracts or lots a trader is allowed to hold simultaneously on a prop firm account. This limit applies to total open positions across all instruments and prevents traders from taking excessive risk.
Why It Matters
- 1Max position size is a hard guardrail that prevents catastrophic losses regardless of your personal risk management.
- 2Even if you wanted to trade 20 ES contracts on a $50,000 account, the firm's 5-contract max position size would prevent it. This protects both the trader and the firm.
- 3Understanding your max position size helps you plan multi-instrument strategies — if you're allowed 10 contracts total and you're holding 6 ES contracts, you can only add 4 more across any other instruments.
Example
- 1Your $100,000 evaluation allows a maximum of 10 ES contracts (or equivalent). You're currently holding 7 ES contracts when you spot a setup on NQ. Each NQ contract counts as approximately 0.5 ES equivalents at your firm.
- 2You can add up to 6 NQ contracts (3 ES equivalents) without exceeding your 10-contract maximum.
- 3Trying to open more would be rejected by the platform.
Common Mistakes
- ✖Not knowing how multi-instrument positions are counted toward the maximum
- ✖Assuming max position size is per-instrument rather than across all open positions
- ✖Running into the limit during volatile markets when you want to add contracts