Butterfly Spread: Bet on Price Precision at Expiry

Key Takeaways

• Butterfly spread is long one lower-strike option, short two middle-strike options, and long one upper-strike option for a small net debit.
• A 95/100/105 call butterfly costs $1.20 debit and pays $3.80 max profit only if XYZ closes exactly at $100 at expiry.
• A common mistake: treating max profit as a realistic target, most winning butterflies capture a fraction of the peak, not the full headline number.
• Butterflies are popular near known pinning levels, monthly expiry magnets, post-earnings strikes, and dividend-capture structures.

What It Is

A standard long call butterfly has three strikes and four contracts, all with the same expiration:

• Long 1 call at a lower strike K1
• Short 2 calls at a middle strike K2 (the body)
• Long 1 call at an upper strike K3

The wings K1 and K3 sit equidistant from the body K2. A long put butterfly uses the same structure with puts and has an identical payoff at expiration. The trade is opened for a small net debit and pays its maximum profit if the stock closes exactly at K2.

A short butterfly reverses every leg. It receives a credit upfront and pays off if the stock closes outside either wing, making it a volatility-long position with capped reward.

The Intuition

A long straddle pays off on any big move, but it is expensive. A short straddle pays on no move, but it has open tails. A long butterfly narrows the bet: you believe the underlying will land in a tight range around one specific price, and you accept that being wrong on either side makes the structure expire near zero.

The butterfly is the option market's equivalent of pinning a target. It is not a prediction that the stock will be quiet in general, it is a prediction that it will close at a specific price at a specific date. That precision is why butterflies are popular around known pinning levels like monthly expiry magnets, post-earnings expected moves, and dividend-capture structures.

How It Works

For a long call butterfly with strikes K1, K2, K3 where K3 minus K2 equals K2 minus K1, and net debit D paid at entry. At expiration let S be the stock price:

max profit = (K2 - K1) - D          (achieved only when S = K2)
max loss   = D                       (when S <= K1 or S >= K3)
lower breakeven = K1 + D
upper breakeven = K3 - D

The payoff is zero below K1, rises linearly to the body, peaks at K2, falls linearly back to zero at K3, and stays at zero above K3. The ratio of max profit to max loss can be high, often 3:1 or 4:1 on narrow butterflies, because the probability of finishing exactly at K2 is low.

A reverse or short butterfly flips the signs. You receive a credit upfront, lose at the body, and profit at or beyond the wings. It is a cheaper way to bet on a big move than a long straddle, with reward capped by the wing width minus the credit.

Worked Example

Stock XYZ trades at $100 a week before expiration. You think the stock will close close to $100 at Friday's close.

You open a long call butterfly with strikes 95, 100, 105 for a net debit of $1.20 per share:

• Buy 1 call at 95 for $5.40
• Sell 2 calls at 100 at $2.40 each (collect $4.80)
• Buy 1 call at 105 for $0.60

Net debit: 5.40 plus 0.60 minus 4.80 equals $1.20 per share, or $120 per contract.

max profit = 5.00 - 1.20 = $380
max loss   = $120
breakevens = 96.20 and 103.80

Three outcomes at expiration:

• XYZ closes at $100. Maximum profit. Short 100 calls expire worthless, long 95 call pays $5. Payoff is $500 minus $120 debit, $380 profit.
• XYZ closes at $102. Long 95 call pays $7, two short 100 calls owe $2 each ($4), long 105 call expires worthless. Net intrinsic $3, less debit $1.20, $180 profit.
• XYZ closes at $107. All four legs are in the money. Payoffs net out to zero inside the wings. Full debit is the loss: $120 loss.

Common Mistakes

1. Treating the max profit as realistic. The headline max profit is only achieved if the stock closes exactly at the body strike. In practice, most butterflies that win capture a fraction of max profit, not the full amount. Model the expected value across the distribution, not just the peak.

2. Ignoring bid-ask slippage. A four-leg structure crosses four bid-ask spreads. On wide or illiquid options, slippage alone can eat the theoretical edge. Either use liquid expirations and underlyings or accept that execution cost is a real drag on any small-debit butterfly.

3. Forgetting that early assignment can break the structure. The two short body calls are American-style on most US equities. Early assignment, especially before an ex-dividend date, converts the butterfly into a short stock position plus the remaining wings. Watch ex-div dates inside the tenor.

4. Closing too early on reverse butterflies. A short butterfly takes in a credit and pays off at the wings, which usually only happens on a big move late in the life of the trade. Closing at the first small move in the right direction often leaves the best payoff behind. Decide in advance on a management rule tied to expected move, not screen P&L.

Frequently Asked Questions

Q: What is a butterfly spread in simple terms? A butterfly spread uses three strikes and four contracts to create a position that profits most when the stock lands near the middle strike at expiration. It costs a small debit and has defined risk on both sides.

Q: How does the butterfly spread affect investment decisions? It lets you express a precise price target with a favourable reward-to-risk ratio. A $1.20 debit can earn $3.80 if correct, but you must be right about the landing price, not just the direction.

Q: What is a real-world example of a butterfly spread? XYZ at $100 one week to expiry. Long 95 call, short two 100 calls, long 105 call. Net debit $1.20. XYZ expires at $100: $380 profit. XYZ expires at $107: full $120 loss.

Q: How can investors use butterfly spreads practically? Use them when you have a specific price target at a specific date, for example, pinning a strike at monthly expiry or fading an expected-move boundary after earnings. Check bid-ask on all four legs; slippage is a real drag on small-debit structures.

Q: How is a butterfly spread different from a vertical spread? A vertical spread has one long and one short leg and profits over a range. A butterfly has three strikes and pays its maximum only at the exact body strike, making it a precision bet rather than a range bet.

Sources

1. Options Industry Council. "Long Call Butterfly." https://www.optionseducation.org/strategies/all-strategies/long-call-butterfly
2. Options Industry Council. "Long Put Butterfly." https://www.optionseducation.org/strategies/all-strategies/long-put-butterfly
3. Options Industry Council. "Short Call Butterfly." https://www.optionseducation.org/strategies/all-strategies/short-call-butterfly
4. Cboe Options Institute. "Options 101." https://www.cboe.com/optionsinstitute/options_basics/options_101/

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.