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Carrying a Capital Loss Back Three Years: How It Works in Canada

Learn how a capital loss carryback lets you apply this year's loss against capital gains from the past three tax years, and how to request it.

Tax5 min readTSLBy the Treadstone Law team · OntarioUpdated 2026-07
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Key takeaways
  • Capital losses in Canada can only be used against capital gains — never against employment income, business income, or other types of income.
  • Calculate your net capital loss for the current tax year on your return, after applying the current capital gains inclusion rate (as of mid-2026, 50% of a capital gain or loss is…

If you sold an investment at a loss this year but paid tax on a capital gain two or three years ago, you may be able to get some of that tax back. Canada's capital loss carryback rule lets you apply a net capital loss from this year against capital gains you already reported — and already paid tax on — in any of the three preceding tax years.

It sounds like a straightforward fix, but the request isn't automatic, and it only works within specific limits. This guide walks through how the carryback works, how to request it, and where taxpayers commonly go wrong.

The Basic Rule

Capital losses in Canada can only be used against capital gains — never against employment income, business income, or other types of income. When your capital losses for the year exceed your capital gains for the year, you're left with a net capital loss.

You have two options for that net capital loss:

You can also split a single year's net capital loss between the two — carrying part of it back and leaving the rest to carry forward — as long as the total doesn't exceed the loss available.

Step by Step: Requesting the Carryback

  1. Calculate your net capital loss for the current tax year on your return, after applying the current capital gains inclusion rate (as of mid-2026, 50% of a capital gain or loss is included for tax purposes — verify the current rate before relying on it, since this figure has been the subject of federal policy changes in recent years).
  2. Identify which of the past three tax years reported a net capital gain you paid tax on.
  3. File a request to carry the loss back — CRA provides a dedicated form (commonly Form T1A, Request for Loss Carryback) for exactly this purpose, filed along with or after your current-year return.
  4. CRA reassesses the earlier year(s) to reduce the capital gain reported in that year, which reduces the tax owing for that year and can generate a refund.
  5. Keep your records — the brokerage statements or transaction records supporting both the current-year loss and the original gain — in case CRA asks you to substantiate either side of the claim.

Carryback vs. Carryforward

Carry It BackCarry It Forward
Applies againstCapital gains from the past 3 tax yearsCapital gains from any future tax year
Best whenYou had a taxable gain in a recent year and want a refund nowYou expect larger gains later, or have no gains in the lookback window
How you claim itA specific request filed with or after your returnAutomatically tracked by CRA and carried forward on your notice of assessment
Time limit3 years back, and it must be a year with a reported gainNone — it carries forward indefinitely

What Actually Counts as a Capital Loss

Not every declining investment produces a usable capital loss. A few things to watch for:

Common Mistakes to Avoid

Frequently asked questions

Do I get an automatic refund once I file the carryback request?

Not immediately. CRA has to process the request and reassess the earlier year before any refund is issued, and reassessments can take time. You'll receive a revised notice of assessment for that earlier year once it's processed.

Can I choose which of the three years to apply the loss against?

Yes, within limits — you can direct how much of the loss goes to each of the three prior years, and how much (if any) you leave to carry forward instead, as long as you don't apply more than the gain reported in each of those years.

What if my losses are bigger than all my gains from the past three years combined?

Any amount you can't use against a prior year's gain simply carries forward indefinitely, to be applied against capital gains in any future year.

Does this apply to losses on a corporation's investments too?

Corporations follow a similar carryback-and-carryforward structure for their own capital losses, though the mechanics of the request differ from a personal return. A tax professional can confirm the right approach for a corporate filer.

This article is general information, not legal advice. Reading it does not create a lawyer-client relationship. Ontario laws, tax rates, and government programs change, and how the law applies depends on your specific facts. For advice about your situation, speak with a licensed Ontario lawyer. Treadstone Law is licensed by the Law Society of Ontario — reach us at 1-844-900-1070 or start a file online.

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