How long do I have to wait to buy back a stock after a loss in Canada?

More than 30 days after the sale, and you must not have bought it in the 30 days before the sale either, or the loss can be denied.

Is a superficial loss gone forever?

Usually not. The denied loss is added to the ACB of the shares you bought back, so you benefit when you sell them, unless they were bought in a TFSA or RRSP.

Does buying in my TFSA trigger the superficial loss rule?

Yes, the CRA applies the rule to repurchases in your TFSA or RRSP, and in that case the loss cannot be recovered later.

Does my spouse buying the same stock count?

Yes. A spouse or common-law partner is an affiliated person, so their purchase in the window can make your loss superficial.

Canada › Guides

Superficial loss rule in Canada for IBKR investors

Updated: 21/10/2026

When the CRA denies a capital loss under the 30-day superficial loss rule, how the denied loss moves to your ACB, and the TFSA and DRIP traps at IBKR.

A capital loss is a superficial loss, and is denied, when you or an affiliated person buy the same security within 30 days before or after the sale and still own it 30 days after the sale. The denied loss is added to the adjusted cost base of the repurchased shares, so it is usually postponed rather than lost — unless the repurchase happened in a TFSA or RRSP.

The three conditions

All of the following must be true for the rule to apply:

You sell a security at a loss.
You, or a person affiliated with you, acquire the same or identical property during the 61-day window running from 30 days before the sale to 30 days after it.
At the end of that window, you or the affiliated person still own the property.

If you sell at a loss and simply stay out of the stock for more than 30 days, the loss counts normally. The window looks backwards too: a purchase made three weeks before the losing sale can trigger it.

Who counts as affiliated

For an individual, affiliated persons include your spouse or common-law partner and a corporation controlled by you or your spouse. The CRA also applies the rule when the repurchase is made in your own TFSA or RRSP. Parents, children and siblings are not affiliated with you for this purpose.

Identical property means property that is the same in all material respects — the same company's shares, for example. A right to acquire the property, such as a call option, can also count. Two ETFs from different providers tracking different indexes are generally not identical, but there is no blanket rule, so judge each case on its facts.

A worked example

You own 100 shares with an ACB of C$6,800. You sell them for C$5,100, a loss of C$1,700, and buy 100 shares back ten days later for C$5,000.

The C$1,700 loss is denied for 2025.
The new shares get an ACB of C$5,000 + C$1,700 = C$6,700.
If you later sell them for C$6,000 with no repurchase, your loss is C$6,000 − C$6,700 = −C$700.

The tax result ends up matching what really happened: C$1,700 lost on the first sale, C$1,000 recovered on the second, a net loss of C$700 — only recognized later.

If you bought back only some of the shares, only part of the loss is denied: the least of the shares sold, the shares bought in the window and the shares held at the end of it, divided by the shares sold. Buying back 40 of 100 shares denies 40 ÷ 100 × C$1,700 = C$680, leaving C$1,020 deductible.

Traps for IBKR investors

Dividend reinvestment. Automatic reinvestment buys new shares every quarter. Selling at a loss shortly before or after a reinvestment date can make part of the loss superficial.
TFSA or RRSP purchases. Selling in your non-registered IBKR account and buying in your registered account still triggers the rule, and because the ACB adjustment goes to a registered account, the loss is lost for good.
Spouse's account. Your partner buying the same stock in their own account counts as well.
Tax-loss selling in December. A buy-back in January still counts if it falls within 30 days of the December sale; the new year does not reset the window.

How to check your own trades, step by step

Export Annual Activity statements from IBKR for 2025 plus the following January, so purchases after late-year sales are visible.
List every sale that produced a loss, in CAD.
For each one, look for purchases of the same security from 30 days before to 30 days after, in every account you and your spouse control, registered accounts included.
Check how many shares were still held at the end of the window and apply the proportional formula.
Report the sale on Schedule 3 but claim only the allowable part of the loss.
Add the denied amount to the ACB of the repurchased shares and carry it forward in your records.

Common mistakes

Looking only at purchases after the sale and missing the 30 days before.
Assuming a different account means a different person.
Denying the whole loss when only some shares were repurchased.
Denying the loss and then forgetting to add it to the new ACB, so it is lost on the next sale too.

A denied loss that you do not track is money you pay tax on twice. Upload your IBKR statement to Brokers.tax and see every losing sale with a repurchase inside the 30-day window marked, so you can claim what is yours and adjust what is not before the CRA does it for you.