Canadian ACB calculator for options: assignments, calls and sales
Put assigned, call assigned, a few buys and a sale. What did your shares really cost you, and what did each sale make or lose? Enter each event and get your running ACB, the Canadian way.
| # | Event | Shares after | ACB after | ACB per share | Gain or loss |
|---|
How it works: Canada pools identical shares at average cost, not first-in first-out. A buy adds its cost and fees to the pool. An assigned put adds the strike minus the premium you got. A sale takes out the pool's average cost for the shares sold, so ACB per share doesn't change; the gain or loss is the proceeds minus fees minus that cost. An assigned call adds its premium to the proceeds. An option that expired or was bought back is its own gain or loss: premium minus the cost to close minus fees. Return of capital lowers the pool; past zero, the extra is a capital gain. Superficial losses are not checked here.
Why your broker's slip may not match
Your broker's T5008 slip often shows the strike as your cost and leaves the premium out. Then a put premium gets reported as a gain once, and again hidden inside a cost that's too high. Your own record is what counts. Keep one line per event, convert US trades to Canadian dollars at that day's rate, and pool every non-registered account that holds the same stock. In a TFSA or RRSP you don't track ACB for tax at all. The same cycle as the default above, step by step, is in ACB after a put is assigned.
What the wheel does to your ACB
In the wheel strategy each assigned put lowers the cost of the shares by its premium. A second assignment at a lower strike pulls the average down further. That can feel like progress, but the default shows the catch: the stock kept falling, and the sale still lost money. Only half of a net capital gain is taxed, and only half of a net loss can be used against gains. If you sold at a loss and a put on the same stock is assigned within 30 days, run the superficial loss calculator too.
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