Understanding Your CRA Notice of Reassessment 2025 — What It Means, How to Respond,

The CRA Notice of Reassessment is one of the most misunderstood—and feared—documents Canadian taxpayers receive. In 2025, CRA’s automated verification system and AI audit tools issue reassessments at record speed, often without full human review. Whether you’re a business owner, self-employed professional, or employee, a Notice of Reassessment can mean additional tax owing, denied deductions, or penalties—and the clock starts ticking the day it’s issued.

You have just 90 days to act. Fail to respond correctly, and the reassessment becomes final and enforceable—with interest compounding daily. But with strategic action and expert representation, most reassessments can be reduced, overturned, or delayed. At Mackisen CPA Auditors Montreal, we don’t just interpret your reassessment—we build a defense that protects your finances, your rights, and your future.

When CRA recalculates your taxes, we recalculate your power.

Legal and Regulatory Framework

Income Tax Act (Canada)

• Section 152(3): Authorizes CRA to reassess a taxpayer’s return after review or audit.

• Section 165(1): Gives taxpayers 90 days to file a Notice of Objection to dispute a reassessment.

• Section 161(1): Accrues daily interest on unpaid amounts from the date of reassessment.

• Section 163(2): Allows 50% gross-negligence penalties for errors CRA deems reckless or intentional.

Tax Administration Act (Quebec)
Revenu Québec has similar reassessment authority and timelines. Quebec taxpayers must file a separate objection to protect their rights provincially.

Mackisen ensures both CRA and Revenu Québec reassessments are managed together—avoiding duplication, miscommunication, and unnecessary penalties.

Key Court Decisions

Venne v. The Queen (1984): Missing objection deadlines makes reassessments final and binding.
Guindon v. Canada (2015): Negligence penalties stand unless taxpayers provide evidence to disprove CRA assumptions.
Jordan v. The Queen (2009): CRA must consider taxpayer-provided documentation before confirming reassessment.
Bédard v. The Queen (2022): Professional representation significantly increases chances of successful reassessment reversal.

These cases prove that a reassessment is not the end—it’s the beginning of your defense.

Why CRA Issues Reassessments

Reassessments occur when CRA finds discrepancies, incomplete reporting, or missing documentation. Common reasons include:

• Unreported T4, T5, or investment income.

• Denied expense or deduction claims (vehicle, meals, home office).

• Adjustments following an audit or pre-assessment review.

• Late-filed returns or missing supporting receipts.

• CRA data matching errors between federal and provincial systems.

Even small mistakes can lead to large reassessments—especially when CRA applies penalties and interest.

Mackisen’s CRA Reassessment Response Strategy

1. Reassessment Review: Analyze CRA’s findings, identify errors, and verify data sources.

2. Evidence Reconciliation: Gather missing documentation or receipts to support disputed claims.

3. Formal Objection Filing: File a Notice of Objection within 90 days to suspend CRA collection activity.

4. Negotiation & Legal Representation: Work directly with CRA Appeals Officers to correct or reduce the reassessed amount.

5. Post-Resolution Monitoring: Ensure CRA updates your account and reverses penalties or overcharges promptly.

Our strategy turns CRA’s assumptions into your advantage—through fact, law, and experience.

Real Client Experience

A Montreal business owner received a CRA reassessment of $87,000 for “unreported income.” Mackisen reconstructed records, proved the amount was already declared, and secured a 100% reversal.
A professional contractor was reassessed $24,500 after CRA denied his vehicle expenses. Mackisen filed an objection, provided evidence, and reduced the liability to just $1,800.

Common Questions

What should I do when I receive a Notice of Reassessment? Contact Mackisen immediately. You have 90 days to file an objection and stop CRA enforcement.
Can CRA collect while I dispute? No—once a valid objection is filed, CRA must suspend collections.
What if I missed the 90-day deadline? Mackisen can request an extension (up to one year) with a written justification.
Will this affect my credit or business? Potentially. Timely action prevents CRA from freezing bank accounts or garnishing wages.

Why Mackisen

At Mackisen CPA Auditors Montreal, we transform CRA reassessments from threats into opportunities for resolution. Our team of CPA auditors and tax lawyers combines accounting expertise, negotiation skill, and legal precision to correct errors and secure your financial protection.

We know CRA’s process inside out—and we use that knowledge to defend you effectively, quickly, and confidently.

Call Mackisen CPA Auditors Montreal today for your 2025 CRA Reassessment Review Consultation. The first consultation is free, and your protection begins immediately.