The superficial loss rule in Canada: the 61-day window

Sell at a loss and buy the same property back within 30 days and the loss is denied, then added to the new units' cost. The window, with an example.

Last checked November 8, 2026. Every rule below names its source; the official pages are listed at the end with their own dates.

In short

The window runs from 30 calendar days before the sale to 30 calendar days after it: 61 days in all.
If you, or a person affiliated with you, buy the same or identical property in that window and still hold it at the end, the loss is a superficial loss.
The denied loss is usually added to the adjusted cost base of the property bought back.

Capital gains calculator (Canada, ACB)

When the rule applies

The CRA's guide T4037: a superficial loss can occur when you dispose of capital property for a loss and both of these happen:

during the period from 30 calendar days before the sale to 30 calendar days after it, you or a person affiliated with you (such as your spouse or a corporation you control) buys the same or identical property;
at the end of that period, you or that person still own it or have a right to buy it.

What happens to the loss

You cannot claim it now. You can usually add it to the adjusted cost base of the property you bought back, so it lowers the gain, or raises the loss, when you sell that property later.

Date	What happens	Result
March 1	Buy 100 shares at $50 ($5,000)	ACB $5,000
June 1	Sell 100 at $40 ($4,000)	Loss of $1,000
June 20	Buy 100 back at $41 ($4,100), inside the 30 days	The $1,000 loss is denied
	New ACB: $4,100 + $1,000	$5,100

Example only, with made-up prices and no fees.

Crypto

The rule is written for capital property in general. The CRA's crypto pages do not discuss it separately, so ask a tax professional how it applies to your trades.

Questions

How long is the superficial loss window?

61 days: 30 calendar days before the sale, the day of the sale, and 30 calendar days after.

Is a superficial loss lost for good?

No. It is usually added to the adjusted cost base of the property you bought back.

Does buying in my spouse's account count?

Yes, purchases by an affiliated person, such as a spouse, count.

Where is the rule explained?

In the CRA's guide T4037, Capital Gains.

Sources

Track prices, rates and your own numbers in one place

Free members get the live market board, the Market Screener, News & Global Markets and Housing Markets. No card needed, and your money always stays on your own exchange.

Create a free account

Last checked November 8, 2026. General information only - not financial, legal, tax or real estate advice. Rules change: confirm with the official source or a licensed professional before you act.