What it means
An option is a contract giving the right, but not the obligation, to buy or sell an asset at a set price by a set date. A butterfly combines four of these contracts so that the trade pays out most when the market barely moves, which is the opposite of what most people assume options are for.
It matters because it expresses a very specific view cheaply. Rather than betting that a share will rise or fall, the buyer is betting that it will finish near a particular level, and the two outer contracts cap the loss so the position cannot run away.
The structure is symmetrical: the gap between the lower and middle strike equals the gap between the middle and higher strike, and these gaps are called the wings. The maximum profit equals the wing width minus the net premium paid, and the maximum loss equals the net premium paid, which is usually small.
The practical drawback is precision. The profitable zone sits between two breakeven points, and if the underlying finishes outside that band the whole premium is lost, so the strategy needs the trader to be right about the level as well as about the calm.
A common variant is the iron butterfly, which builds the same payoff shape from a mixture of puts and calls and is received as a credit rather than paid as a debit. The economics are close to identical; the choice usually comes down to margin requirements and the liquidity of the individual contracts.
In practice
Real-world examples.
Example
A trader expects a pharmaceutical share to stay flat through a quiet month with no trial results due. She builds a call butterfly centred on the current price for a net debit of $0.90 per share and a maximum payoff of $4.10.
Example
A portfolio manager holding an index position wants a cheap way to profit if the index stalls at a well-known resistance level. He places a butterfly centred on that level, risking $2,400 across the position for a possible $9,600.
Example
A retail investor uses an iron butterfly on a technology share the week after earnings, when implied volatility is falling. He collects a $260 credit per contract and keeps it in full if the share closes within a narrow band.
Think of it
“Butterfly profits if price ends up at a specific level-a bet on hitting a target.
Formula
Calculation
Net debit = lower strike premium - (2 x middle strike premium) + higher strike premium
Maximum profit = wing width - net debit
Breakevens = lower strike + net debit, and higher strike - net debit
A trader believes a share currently at $99 will be sitting near $100 in a month. She buys one $95 call at $8.00, sells two $100 calls at $4.50 each, and buys one $105 call at $2.25, all per share.
Net debit is $8.00 less $9.00 plus $2.25, which equals $1.25 per share, or $125 for a standard 100-share contract. The wing width is $5.00, so maximum profit is $5.00 less $1.25, which equals $3.75 per share, or $375. Maximum loss is the $125 paid.
Breakevens are $95 plus $1.25 = $96.25 and $105 less $1.25 = $103.75. If the share finishes at exactly $100, the $95 call is worth $5.00, both $100 calls expire worthless and the $105 call expires worthless, so the profit is $5.00 less $1.25 = $3.75 per share, the maximum.Case study
Seen in the real world.
Marlow Ridge Capital is a fictional boutique fund used purely as an illustrative example. Its options desk had a habit of selling naked options to earn premium in quiet markets, which worked well for several quarters and then produced one loss that wiped out a year of gains.
The risk committee banned uncapped short positions and required every income trade to have defined maximum loss. The desk rebuilt its approach around butterflies and iron butterflies, accepting a lower win size in exchange for knowing the worst case on every ticket before it was placed.
Over the following two years, in this illustrative account, the desk's average monthly return fell by about a fifth while its worst month improved dramatically. The head of desk summarised it plainly at an investor meeting: the fund had traded some upside for the ability to survive being wrong, which was the trade it should have made from the start.
Watch out
Common mistakes.
- Ignoring dealing costs. A butterfly involves four contracts, and on a small position the commissions and spreads can consume a meaningful share of the maximum profit.
- Assuming you can capture the full maximum profit. It is only reached if the underlying finishes exactly at the middle strike at expiry, so realistic planning should assume something less.
- Building unequal wings by accident and then reasoning about the payoff as if it were symmetrical. Uneven strikes create a broken-wing butterfly with a different and sometimes unlimited risk profile.
Questions
People also ask.
Is a butterfly spread a low-risk strategy?
The maximum loss is capped and usually small, but losing the entire premium is the most likely single outcome, so the risk is high in probability terms even though it is limited in size.
When is the best time to open one?
Traders generally prefer to open a butterfly when they expect low movement and when implied volatility is high enough to make the middle contracts they are selling worth a decent premium.
Do you have to hold it until expiry?
No, the position can be closed early, though most of the profit accumulates in the final days as time value drains from the two contracts you sold.
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