Short Butterfly: A Credit Bet on a Breakout

Key Takeaways

• A short butterfly buys two center options and sells one option at each outer strike, for a net credit.
• Maximum profit is the net credit; maximum loss is the wing-to-center distance minus the credit.
• It profits from a move past either outer strike, so it is a long-volatility position despite being a credit.
• The all-call or all-put short butterfly differs from the iron butterfly, which mixes calls and puts.

What It Is

A short butterfly with calls sells one call at the lowest strike, buys two calls at the middle strike, and sells one call at the highest strike. The strikes are equidistant and share an expiration. A short butterfly with puts mirrors this construction with puts.

Because the two outer options you sell are worth more in combination than the two middle options you buy, the trade opens for a net credit. Both the profit and the risk are limited. Unlike an iron butterfly, a short butterfly uses only one option type.

The Intuition

A long butterfly profits when a stock pins near the center strike. The short butterfly reverses that. You want the stock to leave the center and travel past one of the outer strikes, where the position keeps its full credit.

The forecast is for high volatility, a move outside the strike range in either direction. The credit is your reward if the move happens. If the stock settles at the center strike, the structure delivers its worst case.

How It Works

You collect a net credit when you open. The most you can keep is that credit, realized if the stock finishes above the highest strike or below the lowest strike, where the bought middle options no longer drag against you.

The most you can lose is the distance from the center strike to an outer strike, minus the credit, realized if the stock finishes exactly at the center strike. The formulas:

Max profit = net credit
Max loss   = (center-to-wing distance) - net credit
Lower breakeven = lower (outer) strike + net credit
Upper breakeven = higher (outer) strike - net credit

The payoff diagram is a tent inverted into a single trough at the center strike, with flat profit zones once the stock clears either outer strike.

Worked Example

A stock trades at 100. Using calls, you sell the 95 call, buy two 100 calls, and sell the 105 call, all the same expiration. Suppose the net credit is 1.25 per share.

The center-to-wing distance is 5 points. Maximum profit is the 1.25 credit, or 125 dollars, kept if the stock finishes above 105 or below 95. Maximum loss is 5.00 minus 1.25, which is 3.75 per share, or 375 dollars, incurred only if the stock sits exactly at 100 at expiration.

The lower breakeven is the lower outer strike plus the credit, 95 plus 1.25, which is 96.25. The upper breakeven is the higher outer strike minus the credit, 105 minus 1.25, which is 103.75. The stock must clear one of those levels to keep money.

Common Mistakes

1. Confusing it with the iron butterfly. A short butterfly uses one option type across three strikes. An iron butterfly mixes a put spread and a call spread. The structures and labels differ, so confirm which is meant.

2. Reading a credit as a calm-market trade. Most credit strategies want a still stock. The short butterfly is the exception. It needs a breakout, so the credit is not a sign of an income trade.

3. Underrating the required move. The stock must clear an outer strike adjusted by the credit. A move that stalls near the center leaves you near maximum loss.

4. Overlooking commissions on three strikes. With four contracts across three strikes, fees on entry and exit can be heavy relative to a small credit.

5. Letting the position pin. If the stock settles near the center as expiration nears, the trade slides toward maximum loss. Many traders close before pinning risk peaks.

Frequently Asked Questions

What is a short butterfly in simple terms? A short butterfly is a three-strike options trade using all calls or all puts that pays you a credit upfront. You keep the credit if the stock moves past an outer strike in either direction.

How does a short butterfly affect investment decisions? It gives a defined-risk way to bet on a breakout while collecting a credit. Traders use it when they expect a move away from a specific price but want a credit structure.

What is a real-world example of a short butterfly? On a stock at 100, selling the 95 and 105 calls while buying two 100 calls for a 1.25 credit profits if the stock finishes above 103.75 or below 96.25.

How can investors use a short butterfly effectively? Place the center strike where the stock is unlikely to settle, set breakevens within a realistic move, and account for the commissions on four contracts.

How is a short butterfly different from an iron butterfly? A short butterfly uses one option type across three strikes and profits from a breakout. A standard iron butterfly mixes calls and puts and profits when the stock pins to the center.

Sources

1. Fidelity Learning Center. "Short Butterfly Spread with Calls." https://www.fidelity.com/learning-center/investment-products/options/options-strategy-guide/short-butterfly-spread-calls
2. Fidelity Learning Center. "Short Butterfly Spread with Puts." https://www.fidelity.com/learning-center/investment-products/options/options-strategy-guide/short-butterfly-spread-puts
3. Cboe Options Institute. "Mastering Options Strategies." https://pdf4pro.com/view/mastering-options-strategies-cboe-5b3b00.html
4. Rhoads, R. (Cboe). "Butterflies, Condors and Broken Wings." https://www.interactivebrokers.com/webinars/CBOE_Condors_Butterflies_Nov_2010.pdf

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.