Gross negligence: The 50% tax penalty that many taxpayers pay without contesting it

The Canada Revenue Agency (CRA) or Revenu Québec sends you a notice of reassessment. On top of the tax and interest, you are charged a 50% penalty for “gross negligence”.

Many taxpayers pay this penalty without contesting it, assuming the tax authorities are right. Yet the penalty is far from automatic. It is up to the CRA or Revenu Québec to prove that your conduct goes beyond a simple mistake and borders on intentional conduct. That is a difficult burden to meet, and the tax authorities regularly fail before the courts.

This post explains what subsection 163(2) of the Income Tax Act (ITA) and its Quebec counterpart, section 1049 of the Taxation Act (TA), actually cover, what the case law requires as proof, and the procedure for contesting the penalty. It applies whether you are facing only one of the two penalties or, as is common in Quebec, both at once.

What is the gross negligence penalty?

Subsection 163(2) of the Income Tax Act

Subsection 163(2) ITA applies to any person who, knowingly or under circumstances amounting to gross negligence, makes a false statement or omission in a tax return. The minimum penalty is $100.

In most cases, the penalty is 50% of the understated tax, that is, the difference between the tax actually owed and the tax originally reported. It can also apply to related credits and payments, such as the Canada Child Benefit or certain research credits.

The Quebec counterpart: section 1049 of the Taxation Act

In Quebec, the same rule exists in section 1049 of the Taxation Act, which also uses the expression “gross negligence”. The penalty is likewise 50%, this time calculated on the understated Quebec tax. The threshold is the same: it takes more than a simple mistake.

Unreported income is normally missing from both returns, federal and Quebec. The same omission can therefore lead to two penalties, one from the CRA and one from Revenu Québec, each calculated on its own tax. And each must be contested separately.

The burden of proof is on the tax authorities

On appeal, subsection 163(3) ITA places on the Minister the burden of establishing the facts that justify the penalty. In practical terms, the CRA must prove, with clear and convincing evidence, that your conduct meets the threshold of gross negligence. Revenu Québec is subject to an equivalent principle. You do not have to demonstrate your good faith at the outset.

Two thresholds not to be confused

Tax authorities that reopen a statute-barred year do not automatically gain the right to impose the penalty. The two decisions are subject to different thresholds.

To reassess beyond the normal three-year period, subsection 152(4) ITA requires a misrepresentation attributable to neglect, carelessness, wilful default or fraud. That threshold is easy to meet.

The penalty requires much more. In Deyab v. Canada, 2020 FCA 222, inadequate record-keeping was enough to reopen statute-barred years. It was not enough for the penalty: the degree of fault was too low. Poorly kept records can therefore cost a great deal in back taxes without triggering the 50% penalty.

What the courts require as proof

The test: knowledge or gross negligence

Wynter v. Canada, 2017 FCA 195, sets out two ways of justifying the penalty. The first: the taxpayer knew of the false statement. This includes wilful blindness, that is, the deliberate refusal to look into a clearly questionable situation. The second: gross negligence as such, meaning conduct that departs markedly from that of a reasonable person.

In that case, the taxpayer had received unusually large tax refunds after changing tax preparers. She asked no questions. She had also ignored earlier warnings from the Minister. The Court concluded that a taxpayer who turns a blind eye in this way is deemed to have known of the false statement.

The evidence must concern your conduct

The tax authorities’ evidence must relate to your own conduct. Someone else’s conduct is not enough. In Khanna v. Canada, 2022 FCA 84, the Federal Court of Appeal vacated a taxpayer’s penalty: the CRA’s evidence dealt almost entirely with her husband’s actions. This principle is useful if you are a spouse, co-shareholder or partner and the audit focused mainly on someone else.

An honest mistake is not gross negligence

The courts refuse to treat an honest mistake as gross negligence. A taxpayer who gave all of their documents to their accountant, kept their records in order, and always filed their returns shows a real intention to comply. Even if they made a mistake, that profile generally rules out the degree of fault required for the penalty.

Defences that work in practice

In cases where the penalty is vacated, the same elements come up again and again:

• you entrusted your taxes to an accountant or tax specialist and gave them all the relevant documents;
• you ignored no warning signs, such as an unusual refund or tax savings that seemed too good to be true;
• your tax compliance history is spotless;
• you cooperated from the start of the audit, acknowledged the mistake and paid the amounts owing;
• the tax authorities’ evidence concerns a third party or the business in general rather than you.

Your accountant’s mistake, on its own, generally does not justify the penalty if nothing gave you reason to suspect a problem. Still, expect the CRA or Revenu Québec to argue that you should have asked questions.

How to contest the penalty: procedure and deadlines

The notice of objection: 90 days, sometimes more

The first step is the notice of objection. The basic deadline is 90 days from the date of the notice of assessment, federally and in Quebec alike. Individuals have a second deadline: one year after the filing-due date for the return in question. The later of the two applies.

For example, for a 2025 return due by April 30, 2026, you can object until April 30, 2027, even if the 90 days have passed. This second deadline mainly helps when the assessment arrives shortly after filing. If the reassessment covers older years, which is common in gross negligence cases, the 90-day deadline is the one that matters in practice.

If the deadline is missed, an extension of time can be requested within the following year, but it is never guaranteed.

After the objection

If the objection is rejected, the next step is an appeal: to the Tax Court of Canada federally, and to the Court of Québec provincially. This is where the burden of proof under subsection 163(3) takes on its full importance. The tax authorities must present concrete evidence, not mere suspicion.

Voluntary disclosure: act before the tax authorities contact you

The tax authorities have not yet contacted you about the mistake? You may be able to avoid the penalty entirely by correcting the situation yourself.

The CRA’s Voluntary Disclosures Program was overhauled on October 1, 2025. A disclosure made before any contact from the tax authorities entitles you to relief of 100% of penalties and 75% of interest. A disclosure made after a communication from the CRA, such as an education letter, may still qualify, but interest relief drops to 25%. The program closes as soon as an audit or investigation is under way.

Revenu Québec offers a similar program, with one rule of its own: the disclosure cannot cover the current taxation year or the previous one.

In short, voluntary disclosure is only possible if you act before you are identified. Once the audit notice arrives, contesting the penalty is the only option left.

Frequently asked questions

Is gross negligence the same as tax evasion?

No. Tax evasion is a criminal offence that requires an intent to deceive. Gross negligence is an administrative penalty. The required degree of fault is high, but the tax authorities do not have to prove criminal intent beyond a reasonable doubt.

Do I have to pay the penalty while I contest it?

A valid notice of objection generally suspends collection of the disputed amount, federally and in Quebec alike. Interest, however, continues to accrue.

Have a lawyer confirm the exact deadlines and effects before assuming that nothing is payable.

My accountant made a mistake. Am I liable for the penalty?

Not automatically. If you gave them complete and accurate documents and nothing gave you reason to doubt their work, the courts regularly find that there is no gross negligence on your part. The risk increases if obvious warning signs were ignored.

Can I receive both penalties for the same mistake?

Yes, it happens often. The two regimes are administered separately: the same omission can lead to a CRA penalty under subsection 163(2) and a Revenu Québec penalty under section 1049. A joint strategy allows the two files to be coordinated.

In summary

A gross negligence penalty is never automatic. It is up to the tax authorities to prove, with solid evidence aimed at you personally, that your conduct goes well beyond a simple mistake. Objection deadlines, the distinction between a statute-barred year and the penalty, and coordination of the federal and Quebec files: several lines of defence exist even before going to court.

Our team regularly assists individuals and businesses in Quebec and Ontario facing a gross negligence penalty or a contested tax audit. If you have received a notice of assessment of this kind, every day counts. Book an appointment for a free 15-minute initial consultation and have your file assessed.