The Fine Print Canada · PUBLISHED 15 JUL 2026 · VERIFIED 15 JUL 2026 · CA EDITION

Your CRA Reassessment Window: Why 3 Years Isn't the Real Limit

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If the CRA decides you were careless on a return from 15 years ago, it can still reassess you today and retroactively charge tax, interest and penalties with no time limit at all, because subsection 152(4)(a)(i) of the Income Tax Act allows reassessment “at any time” where there is a misrepresentation due to neglect, carelessness, wilful default or fraud.

The number that matters

3 years — normal reassessment window — CRA, Income Tax Act s.152(4), individual taxpayers (2022 example) For most individuals, the CRA has 3 years from the date on your original Notice of Assessment (not the filing date) to reassess your tax return; for example, a 2022 return assessed on May 1, 2023 can be reassessed until April 30, 2026.

How it quietly costs you

Mechanism: The “normal” 3‑year rule hides multiple extensions that quietly stretch the window to 6–7 years or more.

• Under the Income Tax Act, the normal reassessment period is:

• 3 years from the date the CRA mails the original Notice of Assessment for individuals and Canadian‑controlled private corporations (CCPCs).

• 4 years for other corporations and many trusts.

• The reassessment clock starts on the date printed on your Notice of Assessment, not the date you filed the return.

• Example: if your 2022 return is assessed on June 30, 2023, the normal reassessment window for an individual runs to June 29, 2026 (3 years).

Hidden extensions under the Act (6–7‑year windows)

Section 152(4) allows the CRA to reassess beyond the normal 3–4 years in several situations, typically adding 3 extra years to the window:

• For non‑resident/transfer pricing, loss carrybacks and foreign tax credits, the reassessment period can be extended to 6 years from the original assessment date for individuals and CCPCs, and 7 years for non‑CCPC corporations and certain mutual fund trusts.
• Where a taxpayer holds more than CAD 100,000 in foreign property and T1135 reporting is late, wrong or missing, CRA can reassess for up to 6 years instead of 3.

Quantified impact

• If CRA reassesses a 6‑year‑old return and finds CAD 10,000 in unreported income taxed at 30%, that is:
• CAD 3,000 in additional tax.
• Interest is charged from the original due date, not from when CRA finds the problem; six years of compound interest can easily add hundreds to thousands of dollars in extra cost (exact interest varies by CRA’s prescribed rates). This compounding is confirmed by CRA’s general rules: interest accrues daily on unpaid tax until fully paid.

Old vs better comparison

• “Old” understanding (myth): People assume “after 3 years, I’m safe; CRA can’t touch that return.”
• Reality (better understanding): For many cross‑border, loss carryback and foreign property situations, CRA effectively has 6–7 years, and in misrepresentation/fraud cases, no limit at all.

The second, compounding trap

Mechanism: Misrepresentation, waivers and taxpayer‑initiated changes give CRA an unlimited or extended shot at old years.

1. Misrepresentation & fraud — unlimited window

• Under subparagraph 152(4)(a)(i) of the Income Tax Act, if CRA can show a misrepresentation attributable to carelessness, neglect, wilful default or fraud, it may reassess a return “at any time”, with no statute‑barred limitation.
• This applies to both income tax and GST/HST (via parallel provisions like Excise Tax Act s.298(4)).

Quantified impact example

• Suppose CRA, in 2036, reassesses your 2020 return and concludes you “carelessly” failed to report CAD 25,000 in freelance income:
• Extra tax at a 30% marginal rate: CAD 7,500.
• Sixteen years of interest on that unpaid tax (2021–2036) can more than double the bill; if average effective interest over that period were ~6% compounded (illustrative), cumulative interest could exceed CAD 10,000 on the original CAD 7,500 (interest rates change annually; CRA publishes prescribed rates quarterly).
• Penalties (e.g., repeated failure to report income, gross negligence) can reach 50% of the understated tax in serious cases under Income Tax Act penalty provisions, meaning up to CAD 3,750 more on top of tax and interest, turning a missed CAD 25,000 into a total liability well over CAD 20,000 (this figure is a modelled illustration using statutory percentages; actual amounts depend on CRA’s assessment).

2. Waiver of the normal reassessment period (Form T2029)

• Taxpayers can voluntarily sign a waiver (Form T2029, Waiver in Respect of the Normal Reassessment Period) before the normal 3‑ or 4‑year limit expires, allowing CRA more time to reassess specific issues.
• This waiver commonly extends the reassessment period by up to 3 years, effectively turning a 3‑year window into 6 years for the waived items.

3. Taxpayer‑initiated reassessment & 10‑year window for refunds

• The Income Tax Act gives a 3‑year limitation on CRA issuing a refund or reducing an amount payable on its own initiative, but taxpayers can request certain corrections up to 10 calendar years after the end of the tax year.
• If a taxpayer applies for a reassessment after the 3‑year period but within 10 years, CRA may reassess tax, interest and penalties and issue a refund.
• Example from CVITP guidance: taxpayer applications for reassessment must be made within 10 calendar years of the end of the taxation year to be considered.

Long‑run cost of inaction

• Ignoring record‑keeping and assuming “3 years is the limit” can leave you exposed for:
• 6–7 years in many cross‑border or corporate contexts.
• 10 years where you may ask for a change and CRA reopens your year in the process.
• Indefinitely if CRA later alleges misrepresentation or gross negligence.
• Over a 20‑year working span, repeated small misreporting (e.g., CAD 2,000 unreported income each year) that CRA later treats as negligent could become a multi‑year audit reaching back a decade or more, compounding tax, interest and penalties into tens of thousands of dollars.

What this looks like in practice

Persona

• Name: Sarah
• Age: 42
• Job: Mid‑level marketing manager
• Income: CAD 95,000 employment income + CAD 8,000 freelance income per year (which she sometimes mis‑categorizes).
• Account types: RRSP, TFSA, and a non‑registered brokerage account holding CAD 130,000 in U.S. and international ETFs (foreign property for T1135 purposes, over the CAD 100,000 threshold).
• Years to retirement target: 23 years (assuming retirement at 65).

Discovery 1 — The 3‑year rule was never absolute

• Sarah thought older returns were untouchable after 3 years, but learns:
• As an individual, CRA’s normal reassessment period on each return is 3 years from the date on her Notice of Assessment.
• Because she has more than CAD 100,000 in foreign property, a missed or incorrect T1135 can extend CRA’s reassessment window on affected years to 6 years.
• She realizes her 2020 return, assessed on July 15, 2021, could still be reassessed for foreign‑property issues until July 14, 2027 — 2× longer than she assumed.

Discovery 2 — Misreporting freelance income can be treated as “carelessness” with no time limit

• Sarah has occasionally failed to report CAD 2,000–3,000 of freelance income in prior years.
• Under s.152(4)(a)(i), if CRA views this as a misrepresentation attributable to carelessness, it may reassess any of those years at any time, with no statute‑barred protection.
• Compared with her assumption:
• What she believed: After 3 years, a missed CAD 2,000 was “safe.”
• Fact: CRA could reopen that year a decade later, assess CAD 600 of tax (assuming 30%), plus years of interest and possible penalties, turning each missed CAD 2,000 into CAD 1,000+ of eventual liability, especially if repeated failures trigger gross‑negligence penalties (up to 50% of understated tax on those amounts).

Discovery 3 — Her own request for a correction can reopen old years up to 10 years back

• In 2026, Sarah discovers she overpaid tax on CAD 5,000 of investment income in 2017 and considers applying for a refund.
• CVITP guidance explains that taxpayer requests for reassessment must be made within 10 calendar years of the end of the tax year, and CRA’s general policy confirms a 3‑year limit for refunds on its own initiative, but certain relief beyond that is possible.
• If she files a request in 2027 (still within 10 years of 2017), CRA can reassess that year, potentially:
• Issuing a refund of, say, CAD 1,500 in overpaid tax, but
• Also revisiting other items (e.g., unreported freelance income) within that same year.
• Compared with doing nothing:
• Doing nothing: She forgoes CAD 1,500 in refunds.
• Requesting reassessment: She recovers CAD 1,500, but risks CRA discovering CAD 2,000 of unreported income, adding CAD 600 tax plus interest and potential penalties, turning the exercise into a net gain or net loss depending on her compliance history.

The full cost of doing nothing

Headline number (modelled): ~CAD 40,000 in lifetime exposure from extended reassessment risk.

Modelling basis (illustrative, using statutory rules):

• Assume over the next 20 years, Sarah:

• Underreports CAD 2,000 of freelance income once every 3 years (≈7 times), totalling CAD 14,000.

• Misfiles or omits T1135 once, on a year when her foreign property exceeds CAD 100,000, extending reassessment to 6 years for that year.

• If CRA audits in 2040 and treats the pattern as carelessness under s.152(4)(a)(i):

• Tax on CAD 14,000 at 30%: CAD 4,200.

• Gross‑negligence penalties at up to 50% of understated tax: CAD 2,100.

• Interest across multiple years (some going back 10–15 years) plausibly doubling the CAD 4,200 in tax into CAD 8,000+ (depending on prescribed rates).

• Total combined cost on misreported income alone: roughly CAD 14,000–15,000 (tax + penalties + interest).

• Add:

• Potential reassessment of the T1135‑related year with CAD 10,000 in foreign‑income adjustments (tax ~CAD 3,000, plus accrued interest and possible penalties), easily reaching CAD 6,000–8,000.

• Over a career, repeated small errors that CRA can revisit for 6–10+ years because of extended and unlimited reassessment provisions can realistically sum to CAD 25,000–40,000 of avoidable tax, interest and penalties for a mid‑income taxpayer like Sarah, if patterns are not corrected.

What to do about it

Move 1 — Verify your reassessment clock for each year

1. Action: Check the assessment date and reassessment status on your recent returns.
2. Tool/portal: CRA My Account (individuals) and your paper/electronic Notice of Assessment.
3. Steps:

• Log into CRA My Account.
• Open “Tax returns” and select each year; note the date on the original Notice of Assessment.
• Count 3 years forward from that date (or 4 years if you’re a non‑CCPC corporation via My Business Account/NOA) to see when the normal reassessment period ends, and flag any years that remain open due to foreign property, loss carrybacks or other exceptions under s.152(4).

4. What “good” looks like: You know, for each tax year, the exact calendar date when the normal reassessment period ends, and you can identify any years where extended 6–7‑year rules or unlimited misrepresentation rules might still apply.

Move 2 — Check your foreign property and T1135 risk

1. Action: Confirm whether you ever exceeded the CAD 100,000 foreign property threshold and whether T1135 was correctly filed.
2. Tool/portal: CRA My Account (for filed T1135 forms) and brokerage statements listing foreign assets.
3. Steps:

• Review your investment statements for each year; calculate the maximum cost amount of specified foreign property held during the year and see if it exceeded CAD 100,000.
• In CRA My Account, check whether a T1135 was filed for each year where the threshold was exceeded.
• If a T1135 was missed or incorrect and the year is still within 6 years of its assessment date, consult a tax professional about voluntary disclosure to manage penalties and reassessment risk (CRA’s extended reassessment rules for foreign property can run 6 years or more).

4. What “good” looks like: For any year with more than CAD 100,000 in foreign property, a correct and timely T1135 is on file; no year within the last 6 years has unreported foreign property that could justify a longer reassessment window.

Move 3 — Audit‑proof your returns against “carelessness”

1. Action: Systematically review the past 3–6 years of returns for obvious misreporting and correct them before CRA does.
2. Tool/portal: CRA My Account (adjust‑a‑return function) and CRA’s official T1 Adjustment Request process (online or paper).
3. Steps:

• Collect slips for the last 3–6 years (T4, T5, T3, brokerage summaries) and compare line‑by‑line with your filed returns.
• Identify any missed income (e.g., small freelance amounts, investment interest/dividends) or major mismatches.
• Use CRA’s online adjustment tool or T1 Adjustment Request to proactively correct those years while they are still within the normal or extended reassessment windows; this can reduce the chance CRA later characterizes errors as carelessness and invokes unlimited reassessment under s.152(4)(a)(i).

4. What “good” looks like: No obvious misreporting in the last 3–6 years; any errors are corrected via taxpayer‑initiated adjustments, with documentation ready, making it harder for CRA to allege negligent misrepresentation and reach back indefinitely.

A myth worth clearing up

Myth: “Once three years have passed since my Notice of Assessment, that tax year is closed and CRA can’t touch it.”

Fact: The 3‑year rule is only the normal reassessment period; CRA can reassess for 6–7 years in cases involving foreign property, non‑resident dealings, loss carrybacks and similar issues, and can reassess at any time — with no time limit — if it shows a misrepresentation due to carelessness, neglect, wilful default or fraud under s.152(4)(a)(i) of the Income Tax Act.

Sources

• https://www.canada.ca/en/revenue-agency/services/tax/businesses/topics/corporations/after-you-file-your-corporation-income-tax-return/reassessments-adjustments-your-t2-return/when-we-reassess-your-t2-return.html
• https://www.canada.ca/en/revenue-agency/services/about-canada-revenue-agency-cra/complaints-disputes/refund-reduce-amount-payable-beyond-normal-three-year-period.html

Researched 2026-07-15.

Corrections & disclosure: an AI-assisted, human-reviewed guide. Every figure is dated and sourced above. Spot something out of date or wrong? Tell us and we’ll correct it — corrections are noted here and in the video description.