The price formula does not determine the money required to hold a butterfly. Clearing rules, broker policy and the exact dated legs determine margin, while cash variation follows the actual basket path.
Understand the four contract units
A 1:-2:1 butterfly has three different expiry legs but four contract units: one wing, two middle contracts and one opposite wing. Commission schedules and bid-ask costs may apply to all four. Avoid comparing its per-bushel quote with a one-contract P&L without the multiplier.
Ask for the exact margin
Some futures combinations qualify for spread treatment, but the requirement varies by product, expiration, clearing methodology and broker. Maintenance requirements and house add-ons can change. Request the margin estimate for the exact combination rather than assuming a fixed percentage of outright margin.
Watch legging risk and liquidity
If the three legs cannot be filled as one listed strategy, an order in one wing may fill before the other two. This leaves temporary directional exposure. Check the depth and bid-ask spread of each dated month, especially deferred legs, and plan how to unwind the full basket.
Treat drawdown as a cash question
Equal-move cancellation is a mathematical property of the quote, not a guarantee that the middle month will stay aligned. A shock can steepen one calendar gap while flattening the other. Review worst interim historical movement and a stress scenario beyond the sample; deposited margin is not a loss limit.
Test the exact dated structure
Inspect the leg months, historical years and selected window before drawing a conclusion from an average curve.
Open Futures Spread Analyzer →Frequently asked questions
Is a butterfly margin-free because the coefficients sum to zero?
No. Exchange and broker rules recognize residual curve and basis risk and require margin.
What does a four-unit commission mean?
The 1:-2:1 basket has one plus two plus one futures contracts; costs depend on the broker and execution method.
Exchange references
Use the exchange material for product definitions and confirm current specifications, listed combinations and margins with your broker.
Continue the Futures Butterfly Spreads series
Also read Futures Spread Trading and Calendar Spread Trading.
Bring the formula to the chart
Compare a defined structure across historical years and review every leg before making a decision.
Explore the Analyzer →Educational material only, not investment advice. Examples are illustrative. Historical results do not guarantee future performance. Trading costs and slippage are excluded unless explicitly stated.