A butterfly spread is an options strategy that uses four contracts across three strike prices to profit when a stock stays near a specific price by expiration. It caps both your potential gain and your potential loss, making it a defined-risk trade designed for low-volatility situations. The strategy gets its name from the shape of its profit-and-loss diagram, which resembles a butterfly’s wings.
How a Butterfly Spread Is Built
A standard long butterfly spread with calls involves three moves executed simultaneously. You buy one call at a lower strike price, sell two calls at a middle strike price, and buy one call at a higher strike price. All four contracts share the same expiration date, and the distance between each strike price is equal. For example, if a stock trades at $100, you might buy one $95 call, sell two $100 calls, and buy one $105 call. The strike prices are each $5 apart.
The two calls you sell at the middle strike are the “body” of the butterfly, and the calls you buy at the outer strikes are the “wings.” Because the outer calls cost money and the middle calls bring in premium, the trade results in a net debit, meaning you pay a small amount upfront to enter the position. That net debit is the most you can lose.
You can also construct a butterfly spread using puts instead of calls. A long put butterfly works the same way: buy one put at a higher strike, sell two puts at the middle strike, and buy one put at the lower strike. The risk and reward profile is virtually identical to the call version.
Where You Make and Lose Money
The ideal outcome for a long butterfly is that the stock lands exactly at the middle strike price on expiration day. At that point, your lower-strike call is deep in the money, the two short calls at the middle strike expire worthless or at the money, and the higher-strike call also expires worthless. Your profit in that best case equals the distance between the lower strike and the middle strike, minus the net debit you paid to enter the trade.
Using the example above: if the stock finishes at $100, the $95 call is worth $5 per share (or $500 per contract), the two $100 calls expire worthless, and the $105 call expires worthless. Your maximum profit is that $500 minus whatever you paid to set up the spread. If the net debit was $100, your max profit is $400.
The trade has two breakeven points. The lower breakeven is the lowest strike price plus the net debit paid. The upper breakeven is the highest strike price minus the net debit. If the stock finishes outside either of those breakeven points at expiration, you lose money. If the stock moves far beyond the wings in either direction, all the options either expire worthless or offset each other, and your loss is limited to the net debit you paid upfront. That capped downside is one of the main appeals of the strategy.
When Traders Use a Butterfly
Butterfly spreads are directionally neutral bets that the stock will stay in a tight range. Traders typically open them when they believe a stock will trade sideways for the remaining life of the contracts, often ahead of a period with no expected catalysts like earnings announcements or regulatory decisions.
Time decay (known as theta) generally works in your favor with a long butterfly, particularly as expiration approaches and the stock sits near the middle strike. Each passing day erodes the value of the two short options you sold at the middle strike faster than it erodes the outer wings, which boosts the spread’s value. However, if the stock drifts far from the center strike, theta becomes less helpful because the entire position is heading toward its maximum loss regardless.
Changes in implied volatility (vega) tend to hurt a long butterfly. When implied volatility rises, all four options gain value, but the two short middle options gain more collectively than the two long wings. That compresses the spread’s value. Conversely, falling implied volatility helps a long butterfly. This is why traders often enter the position when they expect volatility to decrease or remain low.
Short Butterfly Spreads
A short butterfly is the mirror image. Instead of buying the wings and selling the body, you sell the wings and buy the body. A short call butterfly means you sell one lower-strike call, buy two middle-strike calls, and sell one higher-strike call. This trade brings in a net credit upfront and profits when the stock moves sharply away from the middle strike in either direction. It is essentially a bet on volatility, the opposite of the long version.
The maximum profit on a short butterfly is limited to the net credit received. The maximum loss is the distance between strikes minus that net credit, and it occurs if the stock lands right on the middle strike at expiration.
The Iron Butterfly Variation
An iron butterfly uses both calls and puts instead of all one type. You sell a call and a put at the same middle strike price, then buy a call at a higher strike and a put at a lower strike. The wings are still equidistant from the body. According to the Options Industry Council, the key structural difference is that a long iron butterfly (where you buy the body and sell the wings) produces a negative cash flow upfront, while a short iron butterfly (where you sell the body and buy the wings) brings in a net credit.
The risk and reward math is similar to a standard butterfly, but the iron version can sometimes offer slightly different pricing because it mixes puts and calls, which may have different levels of implied volatility. Many traders choose between the two based on whichever version offers better pricing at the time they want to enter.
Margin and Capital Requirements
If you enter a long butterfly spread (buying the wings, selling the body), you pay a net debit upfront and that is your full capital requirement. Brokers generally require you to deposit the full net debit as initial margin. No additional margin is needed because your risk is fully defined by the structure of the trade.
Short butterfly spreads and iron butterfly spreads that involve selling the wings carry higher margin requirements. FINRA rules require a deposit equal to the difference between the two closest exercise prices (the width of one wing). The net credit received from selling can be applied toward that deposit, reducing the cash you need to have in your account.
Because a butterfly involves four separate contracts, commissions and per-contract fees matter more than they do for simpler trades. Even small per-contract charges multiply by four, and the spread’s maximum profit is often modest in dollar terms. A butterfly that costs $1.00 in net debit with a $5 wing width has a max profit of $4.00 per share, or $400 per spread. If your broker charges $0.65 per contract, that is $2.60 round-trip for opening and another $2.60 if you close, eating into a relatively thin profit window. Many brokers now offer reduced or zero commissions on options, but it is worth checking the per-contract fee before placing the trade.
Practical Considerations
Butterfly spreads look elegant on paper, but hitting maximum profit requires the stock to land on or very near the middle strike at expiration, which is a narrow target. In practice, most traders close the position before expiration once they have captured a portion of the potential profit, rather than holding out for the perfect outcome.
Liquidity matters more for multi-leg strategies. If the bid-ask spreads on the individual options are wide, you may give up a significant portion of your edge just entering and exiting the trade. Stocks and ETFs with high options volume tend to have tighter bid-ask spreads, making butterflies more practical. Many brokers let you enter all four legs as a single order, which helps you get a better fill than placing each leg separately.
The width of the wings determines both your risk and your reward. Wider wings (say, $10 apart instead of $5) increase the maximum profit but also increase the net debit, meaning you have more capital at risk. Narrower wings cost less but give you a smaller profit zone. Choosing the right width depends on how confident you are in the stock staying close to the center and how much capital you want to commit.