Iron
Butterfly

What is an iron butterfly?

An iron butterfly is a four-leg, neutral, defined-risk income trade. You sell one at-the-money call and one at-the-money put at the same centre strike — that short straddle is the engine — then buy one out-of-the-money call and one out-of-the-money put as protective wings. The result is a steep tent-shaped payoff that peaks at the centre strike.

You collect a net credit up front. The strategy pays its maximum when the underlying expires exactly at the centre strike, where both short options expire worthless and you keep the full credit. The wings cap your loss on either side, turning what would be a dangerous naked straddle into a precise, capital-efficient bet on stillness.

Key takeaways

• An iron butterfly is a neutral, defined-risk trade — you want the underlying to pin the centre strike.
• It is built from a short ATM straddle plus long OTM wings (four legs total).
• Maximum profit is the net credit, earned only if price expires at the centre strike.
• Maximum loss is wing width − net credit, capped on both sides.
• The defined risk means far lower margin than a naked short straddle.

How an iron butterfly works

The construction has four legs at the same expiry: sell the ATM call, sell the ATM put, buy an OTM call above, and buy an OTM put below. The two short ATM options generate a fat credit; the two long wings cost a little but cap the risk. The distance from the centre strike to each wing is the “wing width,” and it sets your maximum loss.

This is a short-volatility trade, so time and calm work for you. Theta decay erodes the short straddle in your favour each day the market stays put, and a fall in implied volatility — an IV crush after an event — accelerates the gain. Your enemy is a decisive move in either direction. Because the maximum loss is defined by the wings, the exchange blocks only the SPAN + exposure margin on a capped-risk spread, not the open-ended margin of a naked straddle. NIFTY and Bank Nifty legs are cash-settled.

The numbers that matter

Worked NIFTY example

Suppose NIFTY is near 22,500 and you expect it to drift sideways into expiry. You sell the 22,500 call and 22,500 put, and buy the 22,700 call and 22,300 put as wings, for a net credit of ₹150. With a lot size of 75, you collect ₹150 × 75 = ₹11,250 and the wing width is 200 points (illustrative figures):

• Max profit: ₹11,250, only if NIFTY expires exactly at 22,500.
• Breakevens: 22,500 − 150 = 22,350 and 22,500 + 150 = 22,650.
• Max loss: (200 − 150) × 75 = ₹3,750 beyond either wing.

NIFTY at expiry	Outcome	P&L (1 lot)
22,500 (centre)	Both shorts expire worthless	+₹11,250
22,650 (breakeven)	Short call ITM offsets credit	₹0
22,800	Beyond call wing	−₹3,750
22,350 (breakeven)	Short put ITM offsets credit	₹0
22,200	Beyond put wing	−₹3,750

The peak is sharp and narrow: you earn the most only if the market lands on the nose, but the wings ensure a worst case you can name in advance.

When to use an iron butterfly

• You expect the underlying to stay near a specific level through expiry.
• Implied volatility is high and you expect it to fall, fattening the credit and the IV crush.
• You want a defined, capped risk rather than the open exposure of a short straddle.
• You are happy with a narrow profit zone in exchange for a larger credit than an iron condor.

Risks to respect

• Narrow profit zone: any meaningful move away from the centre quickly erodes the credit.
• Pin risk: the maximum profit needs an exact landing — realistically you book a partial gain.
• Gap risk: an overnight gap can jump straight to the capped loss on one side.
• Commissions and slippage: four legs mean four sets of costs that nibble the credit.

Iron butterfly vs iron condor

Both are defined-risk, short-volatility income trades, and they trade off credit against width. An iron butterfly sells the call and put at the same centre strike, so it collects a richer credit but profits over only a tiny range. An iron condor sells them at separate strikes, collecting less but profiting across a much wider band. Pick the butterfly when you are confident about the pin level; pick the condor when you only know the market will stay range-bound.

Iron butterfly vs short straddle

The iron butterfly is essentially a short straddle with insurance. The short straddle collects a bigger premium but carries undefined, open-ended risk and a heavy margin. Adding the long wings caps the loss, slashes the margin, and trims the maximum reward. If you like the short straddle's thesis but not its tail risk, the iron butterfly is the disciplined version.

Common adjustments

If the underlying drifts toward one wing, traders often roll the untested side closer to recentre the position and collect more credit, or widen the wings to enlarge the profit zone. Some convert into an iron condor by moving the short strikes apart once a directional bias emerges. Closing early — buying back the spread once most of the credit has decayed — is the standard way to avoid pin risk at expiry.

Frequently asked questions

Is an iron butterfly bullish or bearish?

Neutral. It earns the most when the underlying pins the centre strike at expiry, so you want the market to sit still.

What is the maximum profit on an iron butterfly?

The net credit received, realised only if the underlying expires exactly at the centre strike where both short options expire worthless.

What is the maximum loss on an iron butterfly?

The wing width minus the net credit, capped on both sides by the long call and long put — which is why the margin is small.

How is an iron butterfly different from an iron condor?

The butterfly sells the call and put at the same centre strike for a higher credit but a tiny profit zone; the condor uses separate strikes for a lower credit but a wider range.

The bottom line

The iron butterfly is a precise way to bet on a quiet, range-bound market with risk you define before you enter. The fat credit and tidy capped loss are attractive, but the trade-off is a narrow profit zone — you are paid well to be right about where the market settles. Use it when you have a strong view on the pin level and high IV to harvest; widen to an iron condor when you only know the market will stay calm.

Related strategies & terms

• Iron Condor — the wider-range cousin with separate short strikes.
• Short Straddle — the same engine without the protective wings.
• Long Call Butterfly — a debit butterfly built from calls alone.
• Theta · IV Crush · Defined Risk