Superficial Loss Rule Canada: The 30-Day Trap That Kills Your Tax-Loss Harvest

Every year, thousands of Canadian investors sell a losing position, buy it back a week later, and then discover on their T1 that the CRA has quietly denied the loss. The culprit is the superficial loss rule, a 30-day window that catches almost anyone who does not know it exists. Here is exactly how it works and how to work around it legally.

What is the superficial loss rule?

The superficial loss rule is a CRA anti-avoidance provision written into Section 54 of the Income Tax Act. It exists for one reason: to stop investors from selling a losing position, claiming the capital loss on their tax return, and then immediately buying it back so they end up in the exact same portfolio position with a shiny new tax deduction.

The mechanics are simple. If you sell a security at a loss, and either you or an affiliated person buys the same or an identical security within a 61-day window that starts 30 days before the sale and ends 30 days after, and any of those purchased shares are still held on day 30 after the sale, the loss is denied. You cannot use it to offset capital gains this year or carry it back three years or forward indefinitely as you normally would.

The three conditions the CRA tests

For a loss to be denied as superficial, all three of these must be true. Miss any one and you keep the loss.

The rule counts calendar days, not trading days. And it uses the trade date, not the settlement date, in the vast majority of practical situations. Weekend or holiday closes do not extend the window.

Who counts as an 'affiliated person'?

This is where most retail investors get burned. An affiliated person is broader than you think, and the CRA has zero sympathy for accidental triggers.

• Your spouse or common-law partner. If you sell VFV in your non-registered account and your spouse buys VFV in theirs the next week, the loss is denied. This is the single most common accidental trigger.
• A corporation controlled by you, your spouse, or both of you together. Owner-manager selling personal shares and having their opco buy the same security? Denied.
• Your own registered accounts. Selling a stock in your taxable account and then buying it in your TFSA, RRSP, FHSA, or RESP within 30 days permanently denies the loss - and unlike a regular superficial loss, the denied amount is not added to any ACB because the replacement lives in a tax-sheltered account.
• A trust in which you or your spouse have a majority beneficial interest.

What happens to the denied loss?

For a garden-variety superficial loss (you sold in your taxable account and rebought in the same or another taxable account), the denied loss is added to the adjusted cost base of the replacement property. You are not permanently punished - you just have to wait to realize the benefit. The loss returns to you as a smaller capital gain (or larger capital loss) whenever you eventually sell the replacement position, even years later.

For the registered-account version described above, or when the rebuyer is your spouse, the loss vanishes from your return but the ACB adjustment attaches to whoever acquired the replacement. If your spouse triggered it, your spouse gets a higher ACB on their shares - the tax benefit moves to their return, not yours.

Which ETF swaps are safe?

The CRA's guidance on 'identical property' for ETFs and mutual funds is narrower than most investors assume. Two ETFs from different issuers are usually not considered identical, even when they track the same underlying index, because they are legally different trusts with different unit structures. That opens the door to a legitimate tax-loss harvest by swapping issuers.

Two important caveats. First, the CRA has never issued a black-letter ruling that these swaps are always safe - it is the widely accepted professional view based on the definition of identical property, but a very cautious investor might prefer to swap to a slightly different index entirely (say, VFV to VUN, which is broader). Second, a share-for-share exchange of the same issuer's product (e.g., VFV to a Vanguard successor fund) would clearly count as identical and would fail the test.

Common ways investors trigger the rule by accident

• Automatic DRIP - dividends reinvest into the same security. A DRIP purchase inside the 30-day window will partially deny the loss on a pro-rata basis based on the number of reacquired units still held on day 30.
• Biweekly auto-invest at Wealthsimple or auto-purchase orders at Questrade keep buying the same ticker on schedule. If you are planning to harvest a loss, pause these first.
• Employer stock purchase plans (ESPP) and RSU vests keep landing shares. The purchase side of an ESPP or a vest inside the window will trip the rule.
• Rebalancing bands that trigger a buy in the same security days after you sold. Manual rebalancers with alerting can help you avoid this - our alerts feature flags drift without auto-executing.
• Spouse buying in a separate brokerage. The CRA looks at household activity, not per-account. Households that harvest losses should coordinate.

A worked example

Say you bought 200 units of VFV in April 2025 for $120 each ($24,000 ACB). By November 2026 the market is down and VFV is trading at $100. You want to harvest the $4,000 unrealized loss to offset gains you took earlier in the year on Nvidia.

The 30-day rule and crypto

The superficial loss rule applies to cryptocurrency in Canada. The CRA treats crypto as capital property (or inventory, for active traders), and Section 54 applies the same way. Selling Bitcoin at a loss and rebuying within 30 days denies the loss just as it does for VFV.

Crypto investors sometimes assume the rule does not apply because there is no specific CRA crypto guidance page repeating it. The definition of capital property is broad enough to include digital assets, and the CRA has confirmed this position in multiple technical interpretations.

How to run a clean tax-loss harvest at year end

Frequently asked questions