What Happens If You Forget to Report a Capital Gain in Canada?

It is easy to miss a sale. A slip arrives late, shares were sold inside an account you rarely check, or a property changed hands and you assumed the sale was tax-free. Later you realize the gain never made it onto your return.

This article explains why the sale matters, how the gain is worked out, and what to gather before you correct the return with the Canada Revenue Agency (CRA). It does not replace advice on your own situation, especially where penalties are a concern.

This article covers Canadian federal tax law, which applies in every province.

Why an omitted sale matters

A disposition is reported in the calendar year in which the sale or deemed sale occurs, and you must file a return even if no tax is owing. A deemed sale can include a gift of capital property to someone other than a spouse or common-law partner, which is treated as a sale at fair market value on the date of the gift.

If taxable capital gains are higher than allowable capital losses, the difference goes on line 12700 of the T1 return. It is added to your other income and taxed at your marginal rates, so it is not a separate flat tax.

Leaving the sale off means the return understates your income. How CRA responds, and what penalties or interest apply, depends on the circumstances, including whether the omission was an honest mistake.

How much tax is actually at stake

The taxable capital gain is one-half of the capital gain. Because the proposed increase in the inclusion rate never took effect, the one-half rate applies to gains realized in 2024, 2025 and 2026. Finance Canada has confirmed that the government will not proceed with the proposed increase.

If you sold, or are considered to have sold, your principal residence or part of it, you include Form T2091(IND) with your return and report the sale on Schedule 3. Since 2016, the principal residence exemption is allowed only if the disposition and designation are reported on the return, and a late designation may attract a penalty.

Work out the gain before you contact anyone

The gain is the proceeds of disposition minus the property's adjusted cost base (ACB) and the outlays and expenses of selling. On Schedule 3, Part 3, proceeds go in column 2, ACB in column 3, outlays and expenses in column 4, and the gain or loss in column 5. A positive result carries to line 12700, while a negative result does not.

• The date of sale and the sale price, in Canadian dollars.
• What you paid for the property plus acquisition costs such as commissions and legal fees.
• Selling costs, such as commissions.
• Any T3, T4PS, T5 or T5013 slips, since gains on these are generally reported on line 17400 or 17600 of Schedule 3.
• Exchange rates, if the sale was in foreign currency: proceeds at the rate at the time of sale and ACB at the rate when you acquired the property.

Situations that change the picture

• Principal residence: if you sold, or are considered to have sold, your home or part of it, include Form T2091(IND) and report the sale on Schedule 3. Since 2016 the exemption is allowed only if the disposition and designation are reported on the return, and a late designation may attract a penalty.
• Quick resale of a home: a gain on a Canadian housing unit owned for less than 365 consecutive days is deemed business income, not a capital gain, unless a qualifying life event applies.
• Crypto-assets: trading one crypto-asset for another is a disposition, and paying for goods or services with crypto is treated as a barter transaction.
• Business or capital: business profit is fully included in income, while only half of a capital gain is taxable. The line between trading and investing turns on all the facts.
• Losses: a net capital loss can be applied only against taxable capital gains, carried back three years and carried forward indefinitely. If you omitted a loss, it may still be useful.

What to do next

Act sooner rather than later, and keep the approach organized. Gather the sale records, confirm the ACB, and prepare the Schedule 3 calculation for the correct year. Then ask an accountant or lawyer how to submit the correction for that year and whether a voluntary disclosure is available in your case. Time limits, penalty amounts and interest depend on the facts and are worth confirming before you file.

If CRA has already contacted you about the sale, keep its letters and deadlines in front of you and get advice before you respond.

Frequently asked questions