Published: August 13, 2026
Last Updated: August 13, 2026
Overview: Can You Challenge a CRA Tax Reassessment If You Never Got the Original Notice?
In Siam v. Canada, 2026 FCA 91, the Federal Court of Appeal considered whether a taxpayer had proven that an original Notice of Assessment was not sent by the Canada Revenue Agency (CRA), thereby affecting the normal tax reassessment period and the taxpayer’s right to object to a later tax reassessment. The decision clarifies the taxpayer’s burden of proof, the importance of credibility, the limited scope of appellate review of factual findings, and the principle that the doctrine of legitimate expectations cannot create substantive rights contrary to the Income Tax Act.
Facts of the Case in Siam v. Canada
Mohamed Siam appealed a Tax Court decision to the Federal Court that had quashed his appeal concerning a tax reassessment of his 2016 taxation year. The CRA issued the tax reassessment on August 18, 2023. The Tax Court concluded that the tax reassessment had been issued under subsection 152(4.2) of the Income Tax Act because it occurred after the normal tax reassessment period had expired and followed the taxpayer’s request for a refund or reduction of tax. Since subsection 165(1.2) prohibits objections to reassessments made under subsection 152(4.2), the Tax Court held that Mr. Siam’s notice of objection was invalid.
The dispute centred on whether the normal tax reassessment period had actually expired. Mr. Siam argued that he did not receive the original Notice of Assessment issued in 2018 until a later date. According to him, if the notice had not been sent in 2018, the normal tax reassessment period had not yet begun, meaning the 2023 tax reassessment would not fall within subsection 152(4.2).
The Tax Court applied the framework established in Mpamugo v. The Queen and concluded that Mr. Siam failed to prove that the 2018 Notice of Assessment had not been mailed. The Court found that his evidence was not credible, both regarding his assertion that he never received the notice and his suggestion that it had been mailed to the wrong address.
On appeal, Mr. Siam argued that the Tax Court improperly assessed his credibility, that the CRA’s affidavit referred only to the Notice of Assessment being “issued” rather than “mailed,” and that the CRA had led him to believe he possessed a right to object because both the tax reassessment and the responsible CRA officer informed him that an objection could be filed.
The Federal Court of Appeal rejected each argument. It held that the Tax Court committed no palpable and overriding error in assessing the evidence, properly applied the Mpamugo framework, and correctly concluded that the normal tax reassessment period had expired before the 2023 tax reassessment. The Court also held that the doctrine of legitimate expectations cannot create a substantive right that Parliament has expressly denied.
The Importance of Credibility in Siam v. Canada
One of the most significant aspects of Siam is the emphasis placed on credibility.
The Federal Court of Appeal confirmed that the Tax Court may assess a taxpayer’s credibility at the first stage of the Mpamugo framework after hearing all of the evidence. If the Tax Court concludes that the taxpayer has not credibly established that the notice was never mailed, the Court need not proceed further with the remaining steps of the analysis.
As David J. Rotfleisch, a Law Society of Ontario Certified Specialist in Taxation, explains:
“A taxpayer’s testimony is evidence, but the Court must believe it before it can meet the burden of proof.”
This serves as an important reminder that documentary records, correspondence, address history, and other objective evidence often become critical in disputes involving notices issued by the CRA.
Deference to the Tax Court on Factual Findings
The Federal Court of Appeal also emphasized how difficult it is to overturn factual findings on appeal.
An appellate court will intervene only where the lower court made a “palpable and overriding error.” In practical terms, this means an error that is obvious and that affects the outcome of the case. Disagreement with how the trial judge weighed the evidence is generally insufficient.
Mr. Siam argued that the CRA affidavit referred only to the Notice of Assessment being “issued” rather than expressly stating that it had been “mailed.” The Court rejected this argument, finding that the wording did not establish any reviewable error or prevent the Tax Court from concluding that the notice had been sent.
Legitimate Expectations Cannot Override the Income Tax Act
The final issue involved procedural fairness.
The CRA had apparently advised Mr. Siam that he could object to the tax reassessment, and the tax reassessment itself indicated that an objection could be filed. Unfortunately for the taxpayer, the Court held that incorrect information from the CRA cannot create a right that Parliament has expressly removed.
As David J. Rotfleisch cautions:
“Good administration by the CRA is important, but administrative mistakes cannot rewrite the Income Tax Act. Unfortunately, information provided by the CRA cannot be relied upon.”
The Court acknowledged that the CRA should review its practices but confirmed that the doctrine of legitimate expectations affects procedural rights only. It cannot create substantive appeal rights prohibited by legislation.
Implications of the Decision of Siam v. Canada for Canadian Taxpayers
The Federal Court of Appeal’s decision in Siam v. Canada serves as an important reminder that procedural requirements under the Income Tax Act can be just as important as the underlying tax dispute. The case demonstrates that a taxpayer who claims that a Notice of Assessment was not sent bears the burden of proving that claim with credible evidence. Simply asserting that a notice was received late or not received at all may not be enough if there is no objective evidence to support the allegation.
Canadian taxpayers should therefore maintain good records relating to CRA correspondence. Keep copies of Notices of Assessment, Notices of Reassessment, CRA letters, envelopes showing postmarks where available, email notifications from the CRA, and screenshots or records from the CRA’s online portal. These documents may become important evidence if the timing or delivery of a CRA notice is later disputed.
Taxpayers should also promptly document any change of address. Notify the CRA as soon as an address changes, retain confirmation that the update was made, and keep copies of any correspondence or online confirmations showing the date of the change. If a dispute later arises over whether a Notice of Assessment was mailed to the correct address, these records may help establish the relevant facts.
If a Notice of Assessment or Notice of Reassessment appears to have arrived unusually late, do not simply set it aside. Record the date it was received, retain the envelope if it shows a mailing date or postmark, preserve any electronic notifications relating to the notice, and review the applicable objection or appeal deadlines immediately. Where appropriate, contact the CRA to clarify the mailing history and seek legal advice without delay, as statutory deadlines may continue to apply.
David J. Rotfleisch states:
“Tax litigation begins with evidence. If the evidence is weak, even a potentially valid legal argument may never get off the ground.”
Takeaways from Siam v. Canada
Siam v. Canada reinforces several important principles of Canadian tax litigation. The taxpayer bears the burden of proving that a Notice of Assessment was not sent, credibility plays a central role in meeting that burden, appellate courts rarely interfere with factual findings absent a palpable and overriding error, and incorrect advice from the CRA cannot create statutory appeal rights that do not exist. Taxpayers who intend to challenge CRA procedures should preserve objective evidence early and obtain advice from an experienced Canadian tax lawyer before procedural deadlines expire.
Pro Tax Tips: Do Not Assume the CRA Is Correct About Your Rights
In Siam v. Canada, the CRA informed the taxpayer that an objection could be filed, but the Court held that incorrect information from the CRA could not create a legal right that the Income Tax Act does not provide. Before relying on advice contained in CRA correspondence or given by a CRA officer, consider obtaining independent legal advice. An expert Canadian tax lawyer can determine whether a tax reassessment is actually objectionable or appealable under the Income Tax Act and help you avoid spending time and money pursuing a remedy that the legislation does not permit.
Frequently Asked Questions
Who bears the burden of proving that a Notice of Assessment was not sent?
The taxpayer bears the burden of establishing on a balance of probabilities that the Notice of Assessment was not sent.
What is the standard of proof for establishing that a Notice of Assessment was not sent?
The standard is the balance of probabilities, meaning the taxpayer must show that it is more likely than not that the Notice of Assessment was not sent.
What framework is used to assess an allegation that a Notice of Assessment was not sent?
The Court in Siam v. Canada confirmed that the framework established in Mpamugo v. The Queen applies. The taxpayer must first assert that the notice was not mailed, either because it was never received or because it was mailed to the wrong address through no fault of the taxpayer. The Tax Court may first assess the credibility of that evidence before moving to later steps.
What role does the taxpayer’s credibility play in determining whether a Notice of Assessment was sent?
Credibility is fundamental. If the Tax Court finds the taxpayer’s evidence is not credible, the Court may conclude that the taxpayer has failed to satisfy the burden of proof.
When can an appeal court intervene in a lower court’s assessment of evidence?
An appellate court may intervene in the factual finding of a lower court, only if the lower court made a palpable and overriding error in assessing the evidence.
What is a palpable and overriding error?
It is an obvious and serious mistake that affected the outcome of the case.
What is the impact if the CRA’s affidavit states that the Notice of Assessment was “issued” but does not expressly state that it was “mailed”?
This wording alone does not prevent the presumption that the Notice of Assessment had been mailed. The mere fact that an affidavit uses the word “issued” instead of “mailed” does not, by itself, invalidate the tax assessment or prove that the Notice of Assessment was never sent. Additional evidence would be required to establish that the notice was not mailed.
Can the doctrine of legitimate expectations affect substantive rights?
No. The doctrine of legitimate expectations affects procedural rights only. It cannot create a substantive statutory right of objection or appeal that is prohibited by statute.
When does the normal tax reassessment period begin?
The normal tax reassessment period begins when the CRA sends a Notice of Assessment, not when the taxpayer actually receives it. This is based on subsection 152(3.1) of the Income Tax Act. Therefore, simply receiving the notice at a later date does not necessarily delay the start of the normal tax reassessment period.
Can a taxpayer successfully appeal simply because the Tax Court weighed the evidence differently?
No. Disagreeing with how the Tax Court evaluated the evidence is not enough to succeed on appeal. An appellate court will intervene only if the Tax Court made a palpable and overriding error, meaning an obvious error that affected the outcome of the case.
What should a taxpayer do if they never received a Notice of Assessment/Reassessment from the CRA?
If you say you never received a notice of assessment or reassessment, the key issue is usually whether the notice was sent, not whether you actually received it. The normal reassessment period begins when the original notice is sent, and objection deadlines also run from the sending date. A taxpayer alleging non-receipt bears the burden of establishing, on a balance of probabilities, that the notice was not sent. The accepted framework is to assert either that the notice was not received and therefore likely not sent, or that it was sent to the wrong address through no fault of the taxpayer. Credibility is critical, and the court may reject the claim if the evidence is not credible.
How can a taxpayer prove that the CRA sent the Notice of Assessment or Reassessment to the wrong address?
A taxpayer generally must show that the notice was mailed to the wrong address through no fault of the taxpayer. Evidence may include proof that the taxpayer had properly updated the CRA address before the notice was sent, and credible evidence that the CRA nevertheless used an outdated or incorrect address. If the taxpayer’s evidence is not credible, the court may stop there and not require further proof from the CRA. Conversely, if the taxpayer raises a credible allegation, the CRA must prove the notice was sent to the address properly on file.
What is the deadline to object to a valid reassessment?
For most taxpayers, the notice of objection must be served within 90 days after the day the notice of assessment is sent. For an individual other than a trust, or a graduated rate estate, the deadline is the later of: (i) one year after the taxpayer’s filing-due date for the year, and (ii) 90 days after the day of sending of the notice of assessment. The timing runs from sending, not actual receipt. This case of Siam v. Canada confirms that a taxpayer cannot avoid the deadline merely by asserting late receipt unless they establish that the notice was not sent.
DISCLAIMER: This article provides broad information. It is only accurate as of the posting date. It has not been updated and may be out-of-date. It does not give legal advice and should not be relied on as tax advice. Every tax scenario is unique to its circumstances and will differ from the instances described in the article. If you have specific legal questions, you should seek the advice of a Canadian tax lawyer.
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