How to use it
- Enter the units sold, the proceeds and the ACB of those units (from the ACB tracker).
- Enter units bought in the 30 days before and the 30 days after the sale, including purchases by affiliated persons.
- Enter how many units are still held at the end of day 30 after the sale.
- Read the denied amount and the loss you can claim now.
The two conditions
CRA's capital-losses page describes a superficial loss as a loss on a disposition where both of these are true: you, or a person affiliated with you, buy or have a right to buy the same or identical property during the period that starts 30 calendar days before the sale and ends 30 calendar days after it; and you or that affiliated person still own (or have a right to buy) the property 30 calendar days after the sale.
Affiliated persons include your spouse or common-law partner and a corporation controlled by you or your spouse. The legal definition is in section 54 of the Income Tax Act, and paragraph 53(1)(f) is what adds the denied loss to the cost base of the substituted property.
| Situation | Superficial loss? |
|---|---|
| Sell at a loss, buy back on day 12, still hold on day 30 | Yes, for the units bought back |
| Sell at a loss, buy back on day 31 | No: outside the window |
| Buy more on day −20, sell older units at a loss, hold the new units | Yes: purchases before the sale count too |
| Spouse buys the same asset on day 5 and holds it | Yes: affiliated person |
| Sell at a loss, buy back on day 10, sell again on day 25 | Generally no: not held at the end of the window |
Partial superficial losses
When fewer units are bought back than were sold, only part of the loss is denied. The common way to compute it, used in this calculator, takes the smallest of three numbers: units sold, units acquired in the 61-day window, and units held at the end of the window. That share of the loss is denied; the rest can be claimed.
In the default example (illustrative), 100 units with an ACB of $6,000 are sold for $4,000 less $10 in costs, a loss of $2,010. Sixty units are bought in the 30 days after and still held, so 60% of the loss, $1,206, is denied and the remaining $804 can be claimed. The $1,206 is added to the ACB of those 60 units.
Why the window catches people with DCA or bots
Automatic purchases keep running after you sell. If you have a recurring buy and you sell at a loss, any automatic purchase within 30 days before or after the sale counts. The same is true of reward income arriving in the window if it is the same asset. The ACB tracker checks all your rows against the window automatically.
What this calculator does not cover
It does not see accounts you don't enter, such as a spouse's or a corporation's. It does not cover the listed exceptions on CRA's page (for example a disposition on becoming or ceasing to be a resident, or on death). It also assumes the loss is a capital loss; if your activity is a business, different rules apply to the loss.