Tax-Loss Selling Canada: The 30-Day Superficial Loss Trap

Tax-loss selling — realizing a capital loss to offset capital gains in the current year or carry them back or forward — is a legitimate and common Canadian investment strategy. The risk is the superficial loss rule under ITA section 40(2)(g)(i), which denies the loss entirely if you repurchase the same or identical property within a defined window. Getting the mechanics wrong means the deduction disappears without warning and the tax saving you planned for evaporates.

The 61-Day Window

The superficial loss rule applies when you sell a security at a loss and either you or an affiliated person acquires the same or identical property during the period starting 30 calendar days before the sale and ending 30 calendar days after the sale — a total window of 61 calendar days (30 + sale day + 30).

Key points on counting:

• The days are calendar days, not business days or trading days
• The window centres on the settlement date of the sale, not the trade date — though in practice CRA looks at the trade date for the disposition and the acquisition separately. Use the trade date as a conservative proxy for planning
• “Identical property” means the same security (same issuer, same class, same ISIN). Switching from one ETF tracking the S&P 500 to a different ETF tracking the same index may or may not be treated as identical — CRA’s position depends on whether the funds are functionally identical; different providers with different MER or currency structures are generally treated as distinct

If you sell a position at a loss and then repurchase within 30 days on either side of the sale, the loss is denied as a superficial loss.

Who Counts as an Affiliated Person

The affiliated person definition (ITA section 251.1) is broader than most investors expect. It includes:

• Your spouse or common-law partner, including de facto partners
• A corporation you control, or a corporation controlled by your spouse
• Your RRSP, including a spousal RRSP
• Your TFSA
• Your FHSA (First Home Savings Account)
• A trust of which you are a majority-interest beneficiary in certain circumstances

The TFSA and RRSP trap is the most commonly triggered: an investor sells shares at a loss in a taxable (non-registered) account to realize a capital loss, then repurchases the identical security inside their TFSA or RRSP within 30 days. Because the RRSP or TFSA is an affiliated person, the superficial loss rule applies and the capital loss in the taxable account is denied.

The practical implication is that waiting 30 clear days before repurchasing in any of your accounts — registered or non-registered — is necessary to preserve the loss.

What Happens to the Denied Loss

A superficial loss is not permanently lost — it is deferred. The denied loss is added to the adjusted cost base (ACB) of the repurchased property. This means when you eventually sell the replacement shares, your ACB will be higher, reducing the capital gain (or increasing the capital loss) on that future disposition.

For example: you sell 100 shares at a $2,000 loss. The loss is denied as superficial. You repurchase 100 shares at $18 per share. Your ACB becomes $18 + $20 (denied loss per share) = $38 per share. When you eventually sell those shares, your cost base reflects the denied loss.

This ACB adjustment applies only to the property that triggered the affiliated acquisition. If the repurchase was in your RRSP or TFSA, the ACB adjustment is applied to the units inside the registered account — but because registered accounts do not track ACB for tax purposes in the same way, the practical benefit of the deferral may be limited or lost entirely. This is one reason the TFSA/RRSP repurchase scenario is particularly damaging.

Year-End Timing

For the loss to offset capital gains realized earlier in the same calendar year, the sale must settle by December 31. Canadian equities trade on a T+1 settlement cycle (trade date plus one business day), meaning the last trading day for settlement in the same calendar year is typically December 30 in 2026 (since December 31 falls on a Thursday, and December 30 is a Wednesday — one business day prior).

Verify the settlement calendar each year, especially when December 31 falls on a weekend or the exchange has a shortened session.

After the sale, you must wait at least 30 clear calendar days before repurchasing. A sale settling December 30 means the earliest safe repurchase date is January 30 of the following year.

Common Mistakes

Dividend reinvestment plans (DRIPs): If you sell shares at a loss and your DRIP automatically purchases new shares of the same company within 30 days, the DRIP acquisition triggers the superficial loss rule. Suspend DRIP participation before selling.

Automatic ETF purchases: Pre-authorized contribution plans, robo-advisor automatic rebalancing, or payroll-sourced purchases that buy the same ETF within the 30-day window will trigger the rule. Pause automatic purchasing, not just your manual activity.

Spouse’s TFSA purchasing the same security: Even if you are diligent about waiting 30 days in your own accounts, a purchase by your spouse in their TFSA of the identical security within your 30-day window makes your loss superficial.

ACB tracking after repurchase: If you repurchase a different lot of the same security within 30 days at a different price, the ACB calculation across all lots must be recalculated. Failing to update ACB records leads to underreporting of capital gains when the position is ultimately sold.

Use the Tax-Loss Selling Calculator to check whether your scenario triggers the superficial loss rule and how much tax the strategy saves net of the 30-day wait.