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Short straddle vs iron butterfly: what do the wings buy you?

An iron butterfly is a short straddle with protection bought on both sides. Pick the straddle only if you can carry a big margin hold and an open-ended loss. Pick the butterfly if you want the same bet with a loss you know before you start.

Comparison · 7-minute read · Updated 2026-11-09

The short answer

A short Straddle sells a call and a put at the same strike, right where the stock trades. You collect a big credit. You win if the stock sits still. If it runs far either way, the loss keeps growing.

An iron butterfly sells the same straddle, then buys a cheaper put below and a cheaper call above. Those two "wings" cost part of the credit. In return, the loss stops at a fixed number.

Pick the straddle if you want every dollar of credit and can carry a large margin hold. Pick the butterfly if you want the same "stay still" bet with a loss you can size in advance. For most accounts, the butterfly is the only one of the two that fits.

Side by side

One stock, both trades (hypothetical)

Silverleaf Software, a made-up stock, trades at $100. Implied volatility is 30%. Both trades run 30 days.

The short straddle. Sell the $100 call for $3.60 and the $100 put for $3.25. Credit: $6.85, so $685. Break-evens: $93.15 and $106.85.

The iron butterfly. Same straddle. Then buy the $95 put for $1.35 and the $105 call for $1.65. The wings cost $3.00. Credit: $3.85, so $385. Max loss: $5 wings × 100 = $500, minus $385 = $115. Break-evens: $96.15 and $103.85.

What each one ties up

The butterfly's margin is simple: the broker holds the max loss, $115.

The straddle's margin uses the standard formula for uncovered options: the bigger side's requirement, plus the other side's premium. One side is 20% of the stock price, minus how far out of the money it is, plus its premium. Here that is $20 + $3.60 = $23.60 on the call. Add the put's $3.25 and you get $26.85 a share, or $2,685. That is a starting figure. Brokers can and often do ask for more, and it climbs every day the stock moves away. The naked put margin calculator shows the one-side version of that formula.

So the straddle holds about 23 times as much buying power for less than twice the credit.

At expiry

The 12% move is the row to stare at. Silverleaf goes to $112. The straddle loses $515, about four and a half times the butterfly's $115. At 20%, the gap is more than eleven times. And earnings moves of that size happen.

Now the rows at $95 and $105. The straddle is still in profit, +$185. The butterfly is already at its max loss. That is what the wings cost you: a much narrower window. The straddle is in profit anywhere between about $93 and $107. The butterfly is in profit only between about $96 and $104.

The trade-off in one line

The straddle has the better odds and the worse tail. The butterfly has the worse odds and no tail.

Both trades are short Gamma, which means losses speed up as the stock moves, and faster near expiry. On the straddle there is nothing to stop that. On the butterfly, the wings take over once the stock passes $95 or $105. Gamma vs theta shows why the last week is when this bites.

If you know the iron butterfly vs iron condor page, this is the step before it. A butterfly is a straddle with wings. A condor is a strangle with wings. The straddle vs strangle page covers the unprotected pair.

Which one should you pick?

A useful habit: size any straddle as if the butterfly's wings weren't there, and ask what a 20% move would cost. If that number scares you, the butterfly is the honest version of the trade.

The straddle needs naked options approval, the highest level at most brokers. The butterfly needs spread approval. In Canada, TFSAs and RRSPs usually don't allow either, so check your broker's rules.

To see both next to every other strategy, use the options strategy comparison chart. If you'd rather sell one covered option at a time, the wheel strategy has no uncovered side at all.

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