Iron butterflies explained: payoff zones and expiration risk
An iron butterfly concentrates potential profit around one strike. Its large opening credit is offset by a narrow profit region and frequent modeled losses; learn to read the full payoff instead of the maximum-return headline.
By OptionsKing. Publisher and editorial methods.
What you will learn
By the end of this lesson, you should be able to:
- Derive an iron butterfly's expiration profit, break-evens, and loss cap.
- Distinguish maximum-profit dollars from the probability of earning them.
- Compare loss frequency, loss size, and assignment exposure with an iron condor.
An iron butterfly sells a put and call at the same body strike and buys a lower-strike put and higher-strike call for protection, all with the same expiration. For equal-width wings, the intact position's maximum expiration loss is wing width minus net credit. Maximum profit occurs only at the body strike.
The trade
Chipotle (CMG) at $38.40, September 19, 45 days out. The body goes at $38, the nearest strike to the stock.
| Leg | Action | Price | Cash |
|---|---|---|---|
| $34 put | buy 1 | $0.64 | -$64 |
| $38 put | sell 1 | $1.76 | +$176 |
| $38 call | sell 1 | $2.36 | +$236 |
| $42 call | buy 1 | $0.73 | -$73 |
| Net | $2.75 | +$275 |
- Credit: $275, which is five times what the condor on the same chain collected.
- Width: $4 on each side.
- Maximum loss: $400 minus $275 = $125.
- Break-evens: $35.25 and $40.75.
- Return on risk: 220 percent in 45 days.
- Maximum profit: $275, and only if CMG closes at exactly $38.
A structure that pays $275 to risk $125 sounds like an error somewhere. It is not. Look at what it takes to collect it.
Where it ends up
| CMG at expiry | Result | P and L | Odds |
|---|---|---|---|
| Below $34 | full width against you | -$125 | 19.1% |
| $34 to $35.25 | losing | -$1 to -$125 | 8.1% |
| $35.25 to $38 | profitable, rising toward the strike | +$1 to +$275 | 20.8% |
| $38 to $40.75 | profitable, falling away from the strike | +$275 to +$1 | 20.0% |
| $40.75 to $42 | losing | -$1 to -$125 | 7.5% |
| Above $42 | full width against you | -$125 | 24.4% |
Add the two middle rows. 40.8 percent. That is how often this trade finishes anywhere in profit at all.
It loses 59.2 percent of the time. That number goes on the page rather than in a footnote, because every description of an iron butterfly leads with the 220 percent return on risk and most of them never get to this line.
The max profit is a point, not a zone
With a $38 body and $2.75 net credit, expiration P/L per share between the wings is $2.75 - |S - $38|. Moving $1 away from the body reduces profit by $100 for one standard contract set. Beyond either $4-wide wing, the intact spread's expiration loss is capped at $125 before costs.
The $275 headline needs CMG to close at exactly $38.00 on September 19. Not near it. At it.
The odds of finishing within fifty cents of $38 are 7.8 percent. Within a quarter, under 4 percent. The maximum profit on an iron butterfly is a number you will collect approximately never, and quoting a return on risk that assumes it is the single most misleading thing said about this structure.
The model places 40.8% of outcomes inside the profit zone and 59.2% outside. Not every losing outcome is a $125 maximum loss: the rows between a break-even and its wing show partial losses. A risk-neutral pricing identity does not establish the real-world expected return of the trade.
Butterfly against condor, same chain, same day
| Iron butterfly, $38 body | Iron condor, $34 and $43 | |
|---|---|---|
| Credit | $275 | $55 |
| Maximum loss | $125 | $145 |
| Return on risk | 220% | 37.9% |
| Odds of any profit | 40.8% | 67.2% |
| Odds of maximum loss | 43.5% | 20.7% |
| Profit zone width | $5.50 | $10.10 |
Neither column is better. They arrange expiration outcomes differently: this butterfly has a lower modeled probability of any profit but a larger possible profit. Comparing expected returns requires a consistent probability model and execution costs, not only these headline percentages. Suitability depends on the payoff distribution, position size, market view, costs, and ability to manage losses and assignment.
What is worth noticing is the maximum loss row. The butterfly's is smaller, because the credit is so large relative to the wing width. On a high-volatility name with wide wings, a butterfly can be the lower-risk structure in dollars and the higher-risk one in frequency at the same time.
The two mechanical problems
Near expiration, the short body options can contribute substantial negative gamma. The $38 strike is where gamma peaks on the whole chain, and you are short two contracts of it. That means the position's delta swings hard on small moves and the profit and loss is jumpy in the last two weeks in a way the condor's is not. Holding one to expiry is genuinely uncomfortable.
The short legs are at the money into expiry, which is where assignment lives. These are American-style contracts. A short put with little remaining extrinsic value can face early exercise, especially when in the money; simply being at the money one week out is not sufficient to identify a likely assignment, and if CMG finishes anywhere near $38 you are into pin risk on two contracts at once. One gets exercised, the other does not, and you find out on Saturday whether you are long 100 shares or short them.
That second problem is the practical reason most people who run butterflies close them before expiry rather than letting them settle, which means crossing four spreads to get out and giving up part of whatever you made.
When it makes sense
Narrowly. A butterfly is a bet that the stock stays close to one price and that options are currently overpriced relative to that. It wants high implied volatility on the way in and a dead tape afterwards.
It is not an income strategy, it is not passive, and it has nothing to do with the two trades this site is built around. A covered call charges rent on shares you own. A cash-secured put pays you to bid for shares you want. A butterfly is not designed as a stock-ownership strategy, although exercise or assignment can create shares or a short-stock position.
If you are running one, size it by the $125 and not by the contract count, and treat the model's 59.2 percent loss probability as an illustration of the distribution, not an observed or guaranteed loss rate.
Spreads need a higher options approval level than covered calls or cash-secured puts at most brokers, and they are multi-leg orders: two or four legs to fill on the way in and the same on the way out. Every price here is an illustrative worked example computed off one chain, not a quote.
Check your understanding
An equal-width iron butterfly has a $100 body, $5 wings, and a $3 credit. What happens at expiration if the stock is $102?
Show the explanation
The short call has $2 of intrinsic value and the other options have none, so P/L is ($3 - $2) x 100 = $100 before costs. Maximum profit is $300 at exactly $100; break-evens are $97 and $103; maximum expiration loss is $200. Actual stock delivery and assignment must still be managed.
Common questions
What is an iron butterfly?
A short put and call at one body strike, protected by a lower put and higher call with matching expiry and quantities. Its credit and loss cap depend on wing widths; it is not universally the highest-credit structure.
How often does an iron butterfly make money?
This model places 40.8% of outcomes in profit, 59.2% in loss, and 43.5% at maximum expiration loss. Those probabilities are illustrative, not a historical rate; partial losses occur too.
Can I really make 220 percent on an iron butterfly?
Only if the stock closes at exactly the body strike. The odds of finishing within fifty cents of it are 7.8 percent. Quoting the maximum return on risk assumes an outcome you will almost never see.
Is an iron butterfly better than an iron condor?
Compare loss size and frequency, profit range, sensitivity, costs, and management needs. The example's different payoff shapes do not establish identical real-world expected returns or universal superiority.
Sources
Rules and thresholds above were checked against these documents on August 4, 2026. Exchange and broker rules change. Confirm anything you are about to act on with your own broker.
Keep reading
Do the math on your own trade
Every price in this article is an illustrative worked example, not a quote. Read the Learn hub for the rest of the series, and the disclaimer before you act on any of it. Selling options carries real risk of loss, and the loss can be far larger than the premium you collected.