What is a superficial loss?
A superficial loss is a capital loss the CRA does not let you claim, because you effectively never left the investment. It applies when two things are both true:
- You (or a person affiliated with you) buy the identical property in the window from 30 days before to 30 days after the sale; and
- You (or that affiliated person) still own it at the end of that 30-day period after the sale.
When both hold, the loss is denied for now. It is not lost forever — it gets added to the cost base of the shares you repurchased, which we cover below.
The 61-day window
The window is wider than most people assume. It spans 30 days before the sale, the day of the sale, and 30 days after — 61 calendar days in total. A purchase anywhere in that span can taint the loss, including one that happened before you sold.
It is calendar days, not trading days, and the identical-property test is by security: buying a different fund that merely tracks the same index does not trigger the rule, but buying back the same ticker does.
Who counts as an affiliated person
The rule reaches beyond your own accounts. A repurchase counts if it is made by an affiliated person, which includes:
- Your spouse or common-law partner
- A corporation you (or your spouse) control
- A trust of which you are a majority-interest beneficiary
- Your own registered accounts — and a loss pushed into a TFSA or RRSP this way is denied permanently, because those accounts have no ACB to absorb it
This is the trap that catches careful investors: you wait out the 30 days, but your spouse’s automatic contribution rebought the same ETF in week two.
Where the denied loss goes
A denied superficial loss is added to the adjusted cost base of the shares whose repurchase triggered the denial. So the tax benefit is deferred, not destroyed — you recover it when you eventually sell those shares in a non-superficial transaction, because the higher ACB produces a larger loss (or a smaller gain) then.
If you only rebuy some of the shares, only a proportional part of the loss is superficial; the rest you can claim now. Getting that proration right — and carrying the deferred amount into next year’s cost base — is exactly the kind of bookkeeping that spreadsheets lose track of.
Harvesting a loss without tripping the rule
To claim the loss cleanly, neither you nor an affiliated person should hold a repurchase of the identical security at the end of the 30-day window after your sale. In practice that means waiting 31 days before buying back — and pausing any DRIPs or automatic purchases in your and your spouse’s accounts during the window. For a full tax-loss selling strategy, timing is everything.
Use the calculator below to check a specific sale and repurchase, and to get the first safe date you can buy back.