CRA Notice of Reassessment 2026: 90-Day Objection Window & How to Push Back

You filed your T1 in April, received your Notice of Assessment (NOA) in May, banked the refund — and now, eight months later, a Notice of Reassessment (NORA) lands in your CRA My Account inbox saying you owe an extra $2,400 plus interest because the matching program found a T5 slip you forgot to report.

This article walks through exactly what to do: how a NORA differs from your original NOA, the strict 90-day window to file a Notice of Objection, the T400A form, when to pay the disputed amount under protest, and when (and how) to escalate to the Tax Court of Canada.

The difference between NOA and NORA

Your Notice of Assessment (NOA) is what CRA sends after you first file your T1. It confirms (or quietly adjusts) the income, deductions, and credits you reported. If your return passes the automated review, the NOA arrives within 2 weeks of NETFILE filing.

A Notice of Reassessment (NORA) is what CRA sends later — months or years after the NOA — when CRA decides to change the original assessment. Common triggers include:

• Matching program — CRA’s T-slip matching system (T4, T5, T3, T5008, T4A, etc.) cross-references slips reported by employers, banks, and brokerages against what you reported. A missed slip almost always triggers a NORA, often arriving in late autumn after the matching cycle completes.
• Audit findings — a desk audit, in-person audit, or processing review (PPR) of specific deductions or credits resulted in CRA disallowing items.
• Voluntary disclosure or T1-ADJ outcome — you filed an adjustment yourself, and CRA’s processing of that adjustment generated a NORA.
• GST/HST or payroll audit — for sole proprietors or corporations, an indirect-tax or payroll audit can flow through to a personal NORA.
• Information-sharing with the IRS, FINTRAC, or provincial bodies — foreign account or property holdings flagged.

The NORA shows the revised tax owing or refund, the change vs the prior assessment, and a brief explanation of which items CRA adjusted. It also starts the objection clock.

The 90-day objection clock

Under subsection 165(1) of the Income Tax Act, you have 90 days from the date CRA mailed the NORA (NOT the date you received it, opened it, or noticed it in My Account) to file a Notice of Objection on Form T400A.

The 90-day count starts on the date printed on the NORA itself. If you ignore the deadline, your right to object is extinguished — CRA’s reassessment becomes legally final, regardless of how wrong it is.

Late-filing relief exists but is narrow. Under section 166.1, you can apply for an extension of time within one year after the original 90 days expire (so within roughly 15 months of the NORA date) using Form RC4288 — Request for Relief, but you must show that:

1. You had a bona fide intention to object within the 90 days but were unable to do so or instructed someone else to do so on your behalf, AND
2. It would be just and equitable to grant the extension, AND
3. The application is made as soon as circumstances permit.

CRA grants these extensions sparingly. After 15 months total, you have no further administrative remedy — only an application to the Tax Court of Canada itself for late-filing relief, which is even harder to win.

Rule: treat the 90-day mailing date as a hard wall. Set a calendar reminder for day 60 and day 80.

What to do FIRST when you receive a NORA

Don’t fire off an objection in week one. Spend the first 2-3 weeks doing groundwork:

1. Pull your records for the year in dispute. Receipts, bank statements, brokerage statements, the original T-slips, any worksheets you used. If the dispute is about a deduction you claimed, find the supporting evidence now while it’s still locatable.
2. Compare CRA’s adjustment line-by-line against your records. Sometimes the matching program is wrong — a corrected T5 was issued and you reported the corrected amount; CRA’s system pulled the original. Sometimes you genuinely missed a slip. The path forward depends on which.
3. Check the “CRA Account Activities” page in My Account — see the actual T-slip CRA matched against, including the issuer’s full reporting. This often reveals the issuer made an error.
4. Run your own numbers. Use our tax refund estimator or recompute your T1 from scratch. If you can confirm CRA’s number is correct, your decision tree shifts to “pay and move on” rather than “object.”
5. Decide: pay, object, or both. Interest accrues on the disputed amount whether you object or not (more on this below).

Filing a Notice of Objection (T400A)

Once you’ve confirmed CRA’s adjustment is wrong (or arguably wrong), file Form T400A — Notice of Objection via:

• Online: CRA My Account → “Register a formal dispute (Notice of Objection)”. Fastest; instant timestamp for the 90-day clock.
• Paper: mail Form T400A to the CRA Appeals Intake Centre listed on the form for your region.

Include in the objection:

• The NORA reference number and date.
• The tax year(s) at issue.
• A clear statement of the items in dispute (e.g., “CRA disallowed $8,400 of motor vehicle expenses claimed on Form T2125 — these expenses are properly deductible because…”).
• The relief sought (e.g., “reverse the reassessment and restore the original NOA”).
• Supporting facts and evidence — receipts, log books, contracts, prior correspondence. You don’t have to attach everything; you can submit additional documentation later, but a strong initial submission moves faster.

After CRA Appeals receives the objection, an Appeals Officer (independent from the auditor who issued the NORA) reviews. Processing times vary from 6 to 18 months depending on complexity. Simple “missed slip” disputes often resolve in 3-6 months; complex business or international objections can run 18+ months.

The Appeals Officer issues one of three outcomes:

• Notice of Confirmation — CRA upholds the NORA. Your next step is the Tax Court of Canada.
• Notice of Reassessment (variance) — CRA agrees in part. You receive an updated NORA with adjusted figures.
• Notice of Vacation — CRA agrees fully. The original NORA is reversed.

Interest keeps accruing while you object

Filing an objection does NOT pause arrears interest. CRA continues to charge arrears interest compounded daily on the disputed balance throughout the entire objection and appeal process.

The 2026 prescribed rate for tax owing is 10% per year (CRA prescribed rate for overdue taxes = base rate + 4 percentage points, currently 6% + 4%). On a $2,400 balance held for 12 months, that’s roughly $240 of interest stacking on top.

The hedging move: if you’re confident you’ll win the objection, pay the disputed amount under protest now (CRA My Account → “Make a payment” → applies to the reassessed balance). This stops arrears interest immediately. If you eventually win, CRA refunds the amount plus refund interest at the prescribed rate for overpayments (currently 8% annually for individuals, compounded daily) — so you come out roughly whole. If you lose, you avoided the interest hit; the only “cost” is the opportunity cost of the funds for the duration of the dispute.

If you genuinely cannot pay the disputed balance, file the objection and accept that interest will accumulate. CRA does not pursue collection on disputed balances while the objection is active (per CRA’s collections policy), but the interest debt grows.

Worked example

Facts: You’re a self-employed graphic designer in Alberta. You filed your 2024 T1 in April 2025 claiming $8,400 of home-office and equipment expenses on Form T2125. NOA arrived April 28, 2025 confirming a $1,200 refund.

In June 2026 (14 months later), CRA Processing Review requests support for the expenses. You send receipts in July 2026. In August 2026, CRA issues a NORA disallowing $8,000 of the $8,400 on the grounds that the home office was used “only partially for business” and the percentage allocation was inadequately documented. The NORA shows additional tax owing of $2,400 plus interest already calculated at $180 (accrued from May 1, 2025 to August 2026).

Your options:

1. Pay $2,580 now, no objection. Total cost: $2,580. Move on.
2. Object without paying. File T400A in September 2026 with a properly documented home-office percentage calculation, square-footage measurements, and a log of business use vs personal use. Appeals takes ~10 months. Interest accumulates ~$240 over that period on the $2,400 balance.
   • Win: $0 tax + $180 interest already paid is refunded with refund interest (~$15) → net cost ~$0.
   • Lose: owe $2,400 + $180 + $240 = $2,820. Worse than paying upfront.
3. Pay $2,580 under protest AND object. Interest stops immediately. Appeals takes 10 months.
   • Win: refund $2,400 + refund interest on the period CRA held it (~$160 at 8%) → net cost ~$20 (the original $180 interest hit, partly recovered).
   • Lose: no further cost; you already paid. Net cost: $2,580.

Decision rule: if you assess your win probability above ~50%, pay under protest AND object. The downside is bounded; the upside is the refund plus interest.

Tax Court of Canada — when CRA Appeals says no

If CRA Appeals confirms the NORA, you have 90 days from the date of the Notice of Confirmation to file an appeal at the Tax Court of Canada (TCC) under section 169 of the ITA. The TCC is a federal court that hears tax disputes only.

The TCC has two procedures:

• Informal procedure — disputes where the federal tax in dispute is $25,000 or less per tax year (or $50,000 GST/HST or $25,000 in loss determinations). No lawyer required, simplified rules, hearing typically within 12 months, judgment within 90 days of hearing. Filing fee: $0.
• General procedure — anything larger, or any case you’d rather litigate formally. Lawyer strongly recommended. Discovery, expert reports, full evidentiary rules. Timeline: 2-4 years end-to-end. Filing fees: $250-550 depending on amount.

The informal procedure is well-suited to most personal disputes (denied deductions, missed slips, principal residence exemption disputes, disability tax credit denials). The general procedure is for complex corporate, international, or large-dollar matters.

Above the TCC, appeals run to the Federal Court of Appeal and ultimately the Supreme Court of Canada, but these are vanishingly rare for personal tax disputes.

Statute-barred years — when CRA can no longer reassess

The CRA’s reassessment window is governed by subsection 152(4):

• 3 years from the original NOA date for individuals and CCPCs (private corporations).
• 4 years for other corporations and mutual fund trusts.
• 6 years if there was misrepresentation attributable to “neglect, carelessness, or wilful default” or fraud, or if you signed a waiver (Form T2029) extending the period.
• 10 years for transfer-pricing-related adjustments under section 247.

So if a NORA arrives on a return from 5+ years ago and CRA is not alleging misrepresentation/fraud and you didn’t sign a T2029, the reassessment may itself be statute-barred and invalid — that becomes the core of your objection. CRA must affirmatively plead and prove misrepresentation to assess outside the 3-year window; the burden shifts to them.

This is also why never sign a Form T2029 waiver without legal advice. CRA frequently asks taxpayers to sign waivers when a year is approaching the 3-year deadline; signing extends the window indefinitely and gives away a powerful statute-of-limitations defence.

Decision framework

When a NORA arrives:

1. Day 0-7: read it carefully, pull records, compare to your filing.
2. Day 7-30: confirm CRA is right or wrong. If right, pay and move on. If wrong, continue.
3. Day 30-60: draft Notice of Objection (T400A) with evidence. Decide whether to pay under protest.
4. Day 60-90: file objection via My Account. Set calendar reminder for the 90-day deadline.
5. Wait 6-18 months for Appeals decision.
6. If unfavourable: 90-day window to file at TCC informal procedure (under $25k) or consult counsel for general procedure.

Run the impact of the disputed amount through our tax refund estimator to see exactly what’s at stake on your final balance owing or refund.

Related reading

• CRA Notice of Assessment explained — the original NOA that the NORA modifies.
• Missed the April 30 tax deadline — what to do — late-filing penalties that compound the NORA hit.
• T1 adjustment — how to fix your Canadian tax return — the proactive flipside, before CRA reassesses you.

FAQ

Q: I disagree with the NORA but I missed the 90-day deadline. What can I do?

A: File Form RC4288 (Request for Relief) as soon as possible, but only within 12 months of the original 90-day expiry (so within roughly 15 months total of the NORA date). You must show a bona fide intention to object within the original window and a legitimate reason for delay (serious illness, lost mail, reliance on a professional who failed to file). CRA grants these requests sparingly. After 15 months, your only remaining remedy is to apply to the Tax Court of Canada directly for an extension under section 166.2 — much harder.

Q: Can CRA reassess my 2020 return in 2026?

A: For an individual taxpayer, the normal 3-year reassessment window from the 2020 NOA (issued ~May 2021) closed in May 2024. CRA can reassess after that only if it alleges misrepresentation due to neglect, carelessness, wilful default, or fraud (6-year window), or if you signed a Form T2029 waiver. If a 2026 NORA on a 2020 return arrives, check the statute-barred argument first — it may be invalid on its face, and that’s the core of the objection.

Q: Does objecting to a NORA flag me for audit on future returns?

A: No. CRA Appeals is a separate division from Audit; objection records are not shared back to Audit’s risk-scoring system for routine future return selection. Filing an objection is a normal and frequent taxpayer action — CRA processes hundreds of thousands per year. The exception is if your objection reveals systemic issues (e.g., undeclared income across multiple years) — in which case CRA may extend the review. For a routine missed-slip or disallowed-deduction dispute, objecting is the right move with no flagging consequence.