Quick Answer
Exercise or assignment never triggers a gain or loss on the option itself. Calls add the premium to the strike (cost basis for the buyer, sale proceeds for the writer); puts subtract the premium from the strike. When stock is acquired through exercise or assignment, its holding period begins the day after, not on the exercise or assignment date itself.
This is one of the core concepts in options taxation. When an equity option is exercised or assigned, no gain or loss is recognized on the option itself. Instead, the premium is folded into the stock transaction, either as part of the cost basis or as part of the sale proceeds.
What Is the Core Rule for Exercised or Assigned Options?
Upon exercise or assignment:
- No gain or loss is recognized on the option
- The premium is incorporated into the stock transaction
- The holding period of the stock begins fresh on the day after exercise/assignment (the option's holding period does NOT carry over)
What Happens When a Long Call Is Exercised (Buyer Exercises)?
You bought a call and are now exercising your right to buy stock at the strike price.
- Premium paid is added to the strike price to determine cost basis
- Cost basis = Strike price + premium paid
- Holding period of the stock begins the day after exercise
Example: Buy 1 XYZ 50 call at $3, exercise the call
- Cost basis of stock = $50 + $3 = $53 per share
- Holding period starts the day after the exercise date
- If you later sell at $60, your gain = $60 - $53 = $7 per share
What Happens When a Short Call Is Assigned (Writer Is Assigned)?
You wrote a call and the buyer exercised against you. You must sell stock at the strike price.
- Premium received is added to the strike price to determine sale proceeds
- Sale proceeds = Strike price + premium received
- Gain or loss depends on your cost basis in the stock you deliver
Example: Write 1 XYZ 50 call at $3, assigned (you own stock at $45)
- Sale proceeds = $50 + $3 = $53 per share
- Gain = $53 - $45 = $8 per share
- Character (short-term or long-term) depends on how long you held the stock, not the option
What Happens When a Long Put Is Exercised (Buyer Exercises)?
You bought a put and are now exercising your right to sell stock at the strike price.
- Premium paid is subtracted from the strike price to determine sale proceeds
- Sale proceeds = Strike price - premium paid
- Character depends on how long you held the stock you are delivering
Example: Buy 1 XYZ 50 put at $2, exercise the put (stock cost basis $40)
- Sale proceeds = $50 - $2 = $48 per share
- Gain = $48 - $40 = $8 per share
- Character depends on stock holding period
What Happens When a Short Put Is Assigned (Writer Is Assigned)?
You wrote a put and the buyer exercised against you. You must buy stock at the strike price.
- Premium received is subtracted from the strike price to determine cost basis
- Cost basis = Strike price - premium received
- Holding period of the stock begins the day after assignment
Example: Write 1 XYZ 50 put at $2, assigned
- Cost basis of stock = $50 - $2 = $48 per share
- Holding period starts the day after the assignment date
- If you later sell at $55, your gain = $55 - $48 = $7 per share
What Is the Exercise/Assignment Cost Basis Summary?
| Scenario | Effect on Stock | Formula |
|---|---|---|
| Long call exercised | Cost basis of acquired stock | Strike + premium paid |
| Short call assigned | Sale proceeds of delivered stock | Strike + premium received |
| Long put exercised | Sale proceeds of delivered stock | Strike - premium paid |
| Short put assigned | Cost basis of acquired stock | Strike - premium received |
Memory Aid:
Two simple rules cover all four scenarios:
- Calls ADD premiums (to the strike price) for both buyer and writer
- Puts SUBTRACT premiums (from the strike price) for both buyer and writer
Whether the result becomes "cost basis" or "sale proceeds" depends on whether you are buying stock (call buyer, put writer) or selling stock (call writer, put buyer).
| Action | You Are... | Result |
|---|---|---|
| Call buyer exercises | Buying stock | Cost basis |
| Call writer assigned | Selling stock | Sale proceeds |
| Put buyer exercises | Selling stock | Sale proceeds |
| Put writer assigned | Buying stock | Cost basis |
Exam Tip: Gotchas
- "Calls ADD, Puts SUBTRACT" applies to BOTH buyer and writer. The direction of the premium adjustment depends on the option type (call vs put), not on whether you are buyer or writer.
- Cost basis vs sale proceeds is determined by whether you are buying or selling stock. Buying stock (call buyer, put writer) = cost basis. Selling stock (call writer, put buyer) = sale proceeds.
What Are the Holding-Period Rules for Exercised and Assigned Stock?
- When you acquire stock through exercise/assignment (call buyer, put writer), the stock holding period begins fresh on the day after
- The option's holding period does NOT tack on to the stock
- When you sell stock through exercise/assignment (call writer, put buyer), the holding period of the stock you held determines the character
This means a call buyer who exercises after holding the option for 2 years still gets a fresh stock holding period starting the day after exercise.
Exam Tip: Gotchas
- Upon exercise or assignment, NO gain or loss is recognized on the option itself. The premium is folded into the stock transaction.
- The holding period of the stock always begins fresh the day after exercise/assignment. The option's holding period does not tack on. A call buyer who held the option for 2 years still starts a fresh stock holding period the day after exercise.
What Should You Check on Exam Day?
- Can you apply "Calls ADD, Puts SUBTRACT" to find cost basis or sale proceeds for all four exercise/assignment scenarios?
- Do you know no gain or loss is ever recognized on the option itself at exercise or assignment?
- Can you correctly state that an acquired stock's holding period begins the DAY AFTER exercise or assignment, not on the exercise or assignment date itself?