Butterfly Spread: Definition, Setup & Payoff Explained
How a Butterfly Spread Works
A long call butterfly uses three strike prices — all equally spaced — and involves three trades:
| Leg | Action | Strike | Contracts |
|---|---|---|---|
| 1. Lower wing | Buy 1 call | Lower (A) | 1 |
| 2. Body | Sell 2 calls | Middle (B) | 2 |
| 3. Upper wing | Buy 1 call | Upper (C) | 1 |
The strikes are equidistant: if A = $95, B = $100, C = $105. You buy the wings and sell the body. The two short calls at B are funded partly by the long calls at A and C, making the net cost (debit) very low.
The magic of the butterfly is in that middle strike. You want the stock to land exactly there at expiration — that’s where maximum profit occurs. Move away in either direction and profit drops off symmetrically, like the wings of a butterfly.
Butterfly Spread Example
Stock XYZ trades at $100. You build a long call butterfly expiring in 30 days:
| Leg | Strike | Premium |
|---|---|---|
| Buy 1 × $95 call | $95 | −$6.20 (paid) |
| Sell 2 × $100 call | $100 | +$3.40 × 2 = +$6.80 (received) |
| Buy 1 × $105 call | $105 | −$1.50 (paid) |
If XYZ closes at $100 (the body): The $95 call is worth $5, both $100 calls expire worthless, and the $105 call expires worthless. Profit = $5.00 − $0.90 = $4.10 per share. That’s a 456% return on $0.90 risked.
If XYZ closes at $97: The $95 call is worth $2, everything else is worthless. Profit = $2.00 − $0.90 = $1.10. Still profitable, just not at max.
If XYZ closes below $95 or above $105: All legs net out to zero (or cancel each other). You lose the $90 debit — and nothing more.
Payoff by Price Zone
| Stock Price at Expiry | Outcome |
|---|---|
| Below $95 (lower wing) | Max loss: $90 |
| $95 to $95.90 | Partial loss — approaching breakeven |
| $95.90 to $104.10 | Profit zone — peaks at $100 |
| $104.10 to $105 | Partial loss — past upper breakeven |
| Above $105 (upper wing) | Max loss: $90 |
When to Use a Butterfly Spread
You have a specific price target. Unlike an iron condor that profits across a wide range, a butterfly pays off most when you nail the exact landing zone. If you believe XYZ will close near $100 in 30 days, the butterfly is a surgical way to express that view.
Low implied volatility environment. Butterflies are debit trades — you pay to enter. When implied volatility is low, options are cheap and butterflies cost less. If IV then rises, the position can gain value before expiration.
You want asymmetric risk/reward. Risking $90 to potentially make $410 is a 4.5:1 reward-to-risk ratio. Few options strategies offer that kind of leverage with fully defined risk. The catch: the probability of hitting max profit is low.
The Greeks in a Butterfly Spread
Delta is near zero at entry (when the stock is at the middle strike). The position is direction-neutral — you just want the stock to stay put.
Theta works in your favor as expiration approaches — but only if the stock is near the middle strike. Time decay collapses the wings (which you’re long) and the body (which you’re short). Near the body, the short options decay faster, which helps you. Away from the body, theta can work against you.
Gamma is complex. Near the middle strike, gamma is negative (the position doesn’t want the stock to move). Near the wings, gamma flips positive. This dual nature makes gamma risk hard to manage close to expiration.
Vega is slightly negative near the middle strike. A drop in IV helps when the stock is in the profit zone. But vega is small overall — the butterfly is more of a price-target trade than a volatility trade.
Butterfly Variations
| Variation | Construction | Key Difference |
|---|---|---|
| Long call butterfly | Buy 1 lower call, sell 2 middle calls, buy 1 upper call | Classic version — pay a debit |
| Long put butterfly | Buy 1 lower put, sell 2 middle puts, buy 1 upper put | Same payoff as call butterfly (put-call parity) |
| Iron butterfly | Sell 1 ATM put + sell 1 ATM call, buy OTM wings | Collects a credit instead of paying a debit |
| Broken-wing butterfly | Unequal wing widths | Skews the risk to one side — can be entered for zero cost or a credit |
The iron butterfly deserves special mention. It uses the same middle strike but replaces the outer call/put legs with short positions, creating a structure that’s essentially a short straddle with protective wings. It collects a credit upfront (like an iron condor) but with a tighter profit range and higher max profit.
Butterfly Spread vs. Iron Condor
| Feature | Butterfly Spread | Iron Condor |
|---|---|---|
| Entry | Net debit (you pay) | Net credit (you receive) |
| Profit zone | Narrow — centered on one strike | Wide — entire range between short strikes |
| Max profit | High relative to cost | Limited to credit received |
| Probability of max profit | Low | Higher |
| Max loss | Net debit paid (small) | Spread width minus credit (larger) |
| Outlook | Pinpoint price target | Broad neutral range |
Practical Tips
Timing: Butterflies gain most of their value in the final week before expiration, when the options at the middle strike decay fastest. Many traders enter butterflies with 2–4 weeks to go and manage actively in the last few days.
Profit targets: Because the max-profit scenario (stock lands exactly at the body) is unlikely, many traders set a more realistic target of 25–50% of max profit and close when they hit it.
Key Takeaways
- A butterfly spread uses three strikes — buy the wings, sell the body — for a small net debit.
- Maximum profit occurs when the stock closes exactly at the middle strike at expiration.
- Maximum loss is the debit paid — typically very small relative to the potential payoff.
- The reward-to-risk ratio is attractive (often 3:1 to 5:1+), but the probability of max profit is low.
- Best suited for traders with a specific price target and a low-IV environment.
- Variations include put butterflies, iron butterflies, and broken-wing butterflies.
FAQ
Why is it called a butterfly spread?
The payoff diagram has a peaked center (the body) and two flat sides that taper off (the wings) — resembling a butterfly. The profit is highest at the middle strike and falls off symmetrically as the stock moves in either direction.
Is a butterfly spread bullish or bearish?
A standard butterfly is neutral — you want the stock to stay exactly where it is. However, you can shift the body strike above or below the current price to create a bullish or bearish butterfly. The directional bias depends on where you place the center strike relative to the stock.
How much can I lose on a butterfly spread?
The maximum loss is the net debit you paid to enter the trade. In our example, that’s $90 — regardless of how far the stock moves. Both risk and reward are fully defined at entry.
What’s the difference between a butterfly and an iron butterfly?
A long call butterfly pays a debit using all calls (or all puts). An iron butterfly collects a credit by selling an ATM straddle and buying OTM wings for protection. The payoff shape is nearly identical — the difference is construction and whether you pay or collect at entry.
Can I build a butterfly with puts instead of calls?
Yes. A long put butterfly — buy 1 higher put, sell 2 middle puts, buy 1 lower put — produces the same payoff as a call butterfly at the same strikes. Which you use often comes down to liquidity and pricing; put-call parity means the theoretical payoff is identical.