Assignment

What Is Assignment?

Assignment occurs when the holder of an options contract exercises their right to buy or sell the underlying asset, triggering an obligation on the seller to fulfill the contract. When a call is assigned, the seller must deliver 100 shares per contract at the strike price. When a put is assigned, the seller must purchase 100 shares per contract at the strike price.

The Options Clearing Corporation (OCC) processes assignment by randomly selecting a short contract holder from all eligible short positions when exercise notices are filed. Selection is random among brokerage firms, who then distribute assignments among their customers using their own methods. A short option holder can be assigned at any time — not just at expiration.

Why It Matters for Options Traders

Assignment risk is a critical concept for anyone who sells (writes) options, whether covered calls, cash-secured puts, or short legs within spreads. Unlike buying options (where you only lose the premium you paid), selling options creates an obligation — you must buy or sell shares if assigned. Understanding when and why assignment can occur is essential for managing that obligation.

For American-style options (most equity options), assignment can happen any time before expiration if the option is in-the-money and the holder decides to exercise. Most exercise occurs at or near expiration, but early assignment is genuinely possible and most common in two scenarios: when a call is in-the-money and the underlying is about to pay a dividend (the holder exercises to capture it), and when deep in-the-money puts are assigned because the holder prefers cash now rather than waiting.

Defined-risk traders using spreads need to understand assignment within the context of their full position. If the short put in a bull put spread is assigned, the trader is long 100 shares of stock — but they still hold the long put that protects against further downside. Managing or closing the spread before the short option goes deep in-the-money is generally preferable to allowing assignment to occur.

Key Facts

• Trigger: The long option holder exercises their right; the short holder has no choice once exercise is filed
• Timing: American-style options can be assigned any time; European-style (like SPX) only at expiration
• Early assignment risk: Most common around dividend ex-dates for short calls; occasionally on deep ITM puts
• Random selection: The OCC randomly assigns exercise notices; you cannot predict or prevent assignment
• Margin impact: Assignment instantly creates a stock position that may exceed margin limits — monitor carefully
• Mitigation: Close or roll short options before expiration if there’s meaningful in-the-money risk to avoid surprise assignment