Short Straddle - Selling Premium With Undefined Risk
Reviewed by Leon Moyer - Published October 9, 2026 - Last reviewed October 9, 2026
In this lesson
Build a short straddle, state its maximum profit, maximum loss and break-evens, and explain why its risk is undefined and what brokers require before you can sell one.
A short straddle is an options strategy that sells a call and a put on the same stock, at the same strike and expiration, to collect both premiums and profit if the stock stays close to the strike. The most it can make is the premium collected; the most it can lose is unlimited, because the short call has no ceiling.
It is the mirror image of the long straddle. Every dollar the buyer in Long Straddle could lose, the seller can make, and every dollar the buyer could make, the seller can lose. Buyers and Sellers showed why a naked short call is the riskiest of the four basic positions; a short straddle contains one.
A short straddle has undefined risk. A large move in either direction can cost many times the premium collected. The short call's loss has no limit as the stock rises. On the way down the loss stops only at zero: in this lesson's example the straddle loses $50 x 100 minus the whole $343 credit, or $4,657. Brokers allow it only in margin accounts approved for uncovered options, and can raise margin or close positions when the market moves against you.
How does a short straddle work?
You sell one at-the-money call and one at-the-money put with the same expiration, and collect both premiums. At expiration, at most one of the two can be in the money. As long as that one option is worth less than the total premium you collected, you keep the difference.
Worked example
Selling the XYZ 50 straddle
XYZ trades at $50. You sell one XYZ 50 call and one XYZ 50 put, both expiring in 30 days. Prices are Black-Scholes model values at 30% implied volatility and a 4.5% interest rate. Figures are per share x 100, before fees, bid-ask spreads and margin costs.
- Credit: $1.81 for the call plus $1.62 for the put, $3.43 per share, or $343.
- If XYZ finishes at $50: both options expire worthless. You keep the full $343.
- If XYZ finishes at $58: the call is worth $8.00. Loss: ($8.00 - $3.43) x 100 = $457.
- If XYZ finishes at $42: the put is worth $8.00. Same $457 loss.
- If XYZ gaps to $65: the call is worth $15.00, and the loss is $1,157, more than three times the credit.
- Break-evens: $50 - $3.43 = $46.57 and $50 + $3.43 = $53.43.
Illustrative and hypothetical. The ticker and prices are invented for teaching, and the figures exclude commissions, fees, margin interest and taxes, which reduce real results. Past or hypothetical outcomes do not indicate future results.
Short XYZ 50 straddle at expiration: capped gain, open-ended loss
Hover or tap the chart, or focus it and use the arrow keys, to read any price.
Open this trade in the free calculatorShow as table
What are the maximum profit, maximum loss and break-evens?
- Maximum profit: the total premium collected, $343 here, and only if the stock finishes exactly at the strike.
- Maximum loss: unlimited on the upside; on the downside it is the strike minus the premium, $4,657 here, if the stock falls to zero.
- Break-evens: the strike minus the total premium and the strike plus the total premium, $46.57 and $53.43.
The OIC's short straddle guide is blunt about the upside: the maximum risk is unlimited, and the worst case is the stock rising without limit.
Why do traders sell straddles?
Because time and volatility work for the seller. The short straddle earns the theta the buyer pays: with XYZ unchanged at $50 for 15 days, the straddle's model value falls from $343 to about $243, so the seller is ahead $100 without the stock doing anything. Values before expiration add up each leg's model price rounded to the cent, which is how the calculator's Auto premiums show them. A drop in implied volatility helps in the same way.
Sellers usually look for a stock they expect to stay in a range, with implied volatility they believe is higher than the movement to come. The trade-off is lopsided: many small gains, exposed to an occasional large loss.
What can go wrong before expiration?
A short straddle does not have to reach expiration to hurt. Its value is marked to the market every day, and two things raise the cost of closing it: a move away from the strike, and a rise in implied volatility. They often arrive together.
Suppose XYZ gaps to $55 the day after you sell. With 29 days left, buying the straddle back costs about $570 at 30% IV, a loss of $227. If the news also lifts IV to 40%, it costs about $642, a loss of $299. One day in, the loss at 30% IV is already two-thirds of the credit, and it can keep growing for the 29 days that remain.
The credit, and the cost to close after an overnight gap
Short XYZ 50 straddle, per position
What do brokers require to sell a straddle?
Because the short call is uncovered, a short straddle needs a margin account and your broker's approval for uncovered option writing, usually its highest options level. Under FINRA Rule 4210, the minimum margin when a put and a call on the same stock are both short is the requirement on whichever leg needs more, plus the current market value of the other option. It is recalculated as prices move, so a move against you can trigger a margin call, and brokers can require more. Course 3's Ratio Spread Risk lesson explains the uncovered-option margin formula and FINRA's approval rules in detail; check your own broker's options agreement and margin schedule.
How does assignment work on a short straddle?
Both legs are American-style options on most U.S. stocks, so either can be assigned on any business day, as the OIC's assignment FAQ explains. The OIC's short straddle guide notes that early assignment is more likely for the call just before an ex-dividend date, and for the put once it is deep in the money.
At expiration, the OCC automatically exercises equity options that are in the money by $0.01 or more unless the holder instructs otherwise through their broker. So unless XYZ closes exactly at $50, one leg will normally be assigned, leaving you short 100 shares (from the call) or long 100 shares (from the put). A close near the strike also leaves you unsure which side, if either, will be exercised. Many traders close a short straddle before the final day for this reason. Brokers differ on cutoff times and on whether they close expiring positions near the strike, so check your broker's policy.
Check your understanding
You sell the XYZ 50 straddle for $3.43. Where are the break-evens at expiration?
Show answer
$46.57 and $53.43: the $50 strike minus and plus the $3.43 credit.
XYZ finishes at $60. What is the short straddle's result?
Show answer
A loss of $657. The call is worth $10.00, the put expires worthless, and ($10.00 - $3.43) x 100 = $657.
Why is a short straddle's maximum loss described as unlimited?
Show answer
It includes an uncovered short call. If the stock keeps rising, the call keeps gaining value, and there is no price at which the seller's loss stops growing.
Key takeaways
- A short straddle sells a call and a put at the same strike and expiration, collecting both premiums.
- Maximum profit is the premium collected, kept in full only at the strike; maximum loss is unlimited on the upside; break-evens are the strike plus and minus the premium.
- Time decay and falling implied volatility help the seller; a move or a rise in volatility can cause losses well before expiration.
- It requires a margin account and uncovered-writing approval, and either leg can be assigned early.
Common questions
What is the maximum loss on a short straddle?
There is no fixed maximum. The short call's loss grows without limit as the stock rises. On the downside, the loss is large but limited: the strike minus the premium collected, per share, if the stock falls to zero.
When does a short straddle make money?
When the stock finishes between the two break-evens, the strike plus and minus the premium collected. The full premium is kept only if the stock finishes exactly at the strike. Closing early after time decay or a drop in implied volatility can also lock in a gain.
Do you need margin to sell a straddle?
Yes. A short straddle includes an uncovered call, which requires a margin account and, at most brokers, their highest options approval level. FINRA sets minimum margin for the position, and brokers can require more.
What happens to a short straddle at expiration?
Unless the stock closes exactly at the strike, one of the two options is in the money and will normally be exercised, so you are assigned on it. That leaves you short or long 100 shares per contract, unless you close the position first.