Claimed a Loss You Shouldn't Have? Changing Your Return

17 October 2026 · en-CA · Educational information · No affiliate links

Educational information only. Not tax, legal or investment advice. We are not the CRA and are not affiliated with it. Check canada.ca and consider a qualified Canadian tax professional. Sources checked October 17, 2026. Anything marked expected should be re-checked. Examples use made-up numbers. This page contains no affiliate links.

Short answer: The CRA says you can request changes to a filed individual return without filing a new one. You must wait until you receive your notice of assessment, then use Change my return in your CRA account (or ReFILE in certified software) or send Form T1-ADJ by mail if you cannot do it online. Online, "Change my return" works for tax year 2016 onwards; for 2015 or earlier you must use Form T1-ADJ by mail. If you claimed a capital loss that turns out to be a superficial loss under section 54 of the Income Tax Act, this is the route to correct it. The CRA says a refund cannot be issued for an adjustment request made more than 10 calendar years after the tax year. For a superficial loss the effect is usually extra tax rather than a refund.

When is a loss superficial? (section 54, read)

A loss is superficial where, during the period from 30 days before to 30 days after the disposition, you or a person affiliated with you acquires the same or an identical property (the substituted property), and at the end of that period you or an affiliated person own it or have a right to acquire it. A right to acquire a property is deemed identical to it (other than as security only). See the rule and exceptions.

What section 40(2)(g) does

If you claimed a loss that was superficial, the loss is nil for that year to the extent that it is superficial (paragraph 40(2)(g)). If you are the person who acquired the substituted property, the CRA says you can usually add the denied amount to its ACB, so fix both the Schedule 3 loss and the ACB records. Corporations, trusts and partnerships follow subsections 40(3.3) and 40(3.4) instead (exceptions page).

How to correct a filed return (CRA, read 17 October 2026)

  1. Wait for your notice of assessment for the return you want to change.
  2. In your CRA account choose Tax return, then Change my return, pick the year and follow the steps; save your confirmation number and summary.
  3. If you must mail it, complete T1-ADJ with the tax year, the changed lines, revised amounts and your contact details; send it separately from your current-year return.
  4. For online requests, the CRA says you provide documents only if it asks; by mail, attach supporting documents for the entire revised amount.

You cannot use "Change my return" to make or revise an election, and the CRA says a request that includes a loss carryback amount can take up to 35 weeks.

What changes on Schedule 3

Correct the loss and, where the loss was superficial, the cost of the substituted property (added to ACB example; Schedule 3 line 7).

Made-up example

You sold coins at a loss on December 15 and bought the same coin on December 20, then claimed the loss. After receiving your notice of assessment you spot the issue and use Change my return to remove the claimed loss for that year.

Related

Tax-loss selling dates and window · Records

FAQ

Can I change a return I filed through a preparer? The CRA says the return must have been filed by you or your tax preparer.

Are there penalties for correcting? The CRA says you may be able to reduce or avoid penalties and interest by voluntarily correcting your tax affairs, either by changing your return or through the Voluntary Disclosures Program. The VDP page says the mistake must be at least one year past the filing due date. Whether a penalty applies to your case is for the CRA to decide.

What we could not verify

Sources (official)