The characteristic of butterfly is that the directions of two sides and the middle are opposite, and the cumulative number of two sides is the same as that of the middle. Break-even is very simple, as long as you accumulate money in long and short directions.

Butterfly arbitrage is a synthetic form of arbitrage trading, involving three contracts. Three kinds of contracts in futures arbitrage are short-term contracts, long-term contracts and longer-term contracts, which we call near-end contracts, mid-range contracts and far-end contracts.