How much capital would I need if my short call gets assigned and I don't own the shares?

How this works

• Shares owed equals 100 shares per contract, the standard size for an equity option contract unless yours has been adjusted for a corporate action.
• If you don't already own the shares, assignment on a short call means buying them at the current market price to deliver them at your strike price. The capital figure above reflects that full purchase, since your broker generally needs to see the buying power for it even though the strike proceeds settle as part of the same transaction.
• This calculator assumes shares are bought at today's price you entered. The actual price at the moment of assignment, usually the next trading day, can be higher or lower.
• An uncovered (naked) short call carries risk that is not capped the way a covered call or a defined-risk spread is, since there is no ceiling on how high a stock can trade before expiration.
• This tool does not check your broker's specific margin requirements, which are typically higher than the figures shown here to account for price movement before you can close the position.