What Is a Butterfly Spread?
A butterfly spread is a three-strike, four-contract options strategy that profits when the underlying stock closes near the middle strike price at expiration. It consists of buying one option at the lower strike, selling two options at the middle strike, and buying one option at the upper strike. All options share the same expiration and are either all calls or all puts.
The long butterfly is a defined-risk, defined-reward strategy with a very favorable risk/reward ratio. The maximum profit can be several times the maximum loss, but it requires the stock to close very near the middle strike. This makes it an ideal strategy for traders who have a strong conviction about where the stock will settle by expiration, such as pinning behavior near round numbers.
A long call butterfly: Buy 1 lower call + Sell 2 middle calls + Buy 1 upper call. The wings (long options) are equidistant from the body (short options). Net cost is a debit. Maximum profit occurs at the middle strike at expiration.
Butterfly Spread Formulas
- 1Net debit = $1.00 per share ($100 per butterfly)
- 2Max profit = ($100 - $95 - $1.00) × 100 = $400
- 3Max loss = $1.00 × 100 = $100
- 4Lower breakeven = $95 + $1.00 = $96.00
- 5Upper breakeven = $105 - $1.00 = $104.00
- 6Max ROI = $400 / $100 = 400%
- 7Profit zone: $96.00 to $104.00
Butterfly Types Comparison
| Type | Construction | Cost | Best When |
|---|---|---|---|
| Long Call Butterfly | Buy 1 lower call, sell 2 middle calls, buy 1 upper call | Debit | Neutral, expect pin at middle strike |
| Long Put Butterfly | Buy 1 upper put, sell 2 middle puts, buy 1 lower put | Debit | Neutral, expect pin at middle strike |
| Iron Butterfly | Sell ATM straddle + buy OTM strangle | Credit | Same payoff as long butterfly but credit-based |
| Broken Wing Butterfly | Unequal wing widths | Debit or Credit | Directional bias with neutral center |
Trading Butterflies Effectively
- Butterflies have the best risk/reward ratio of any defined-risk strategy
- Max profit only occurs at one exact price, making it hard to achieve
- Very low cost (often $0.50-$2.00 per butterfly)
- Commission costs can be significant due to 4 legs
- Popular for expiration-day and expiration-week trading
Because butterflies cost very little relative to their maximum potential profit, they can be used as low-cost directional or pinning bets. Even if only 1 in 4 butterflies reaches 50% of max profit, the strategy can be overall profitable.
Butterfly spreads involve 4 contracts across 3 strikes, which means execution can be challenging in illiquid options. Always use limit orders for the net debit and trade butterflies on liquid underlyings (SPY, QQQ, AAPL, etc.) with tight bid-ask spreads.