On May 15, 2025, the Ontario provincial government released its 2025 budget, and with it came no signs of a general reassessment of property taxes. For the foreseeable future, property tax assessments in Ontario will continue to be based on a January 1, 2016 valuation date. That said, after nearly a decade and counting with the same valuation date, a decision from the Assessment Review Board ("ARB") is sparking debate about how many valuation dates there are in Ontario's property tax assessment system.
In General Motors of Canada Company v Municipal Property Assessment Corporation Region 23, 2024 CanLII 55068 (ON ARB) ("General Motors"), the ARB interpreted the Assessment Act, S.O. 1990 C. A.31 (the "Act") as prescribing different valuation dates for omitted and supplementary assessments made during the assessment cycle. If not overturned, this interpretation may cause significant increases in tax liabilities for Ontario taxpayers.
The rise of multiple valuation dates
An omitted assessment is issued under section 33 of the Act to correct an omission from the tax roll (i.e. the value of a building was missed and is now being accounted for on the tax roll). A supplementary assessment is issued under section 34 of the Act to account for certain circumstances listed under that section (i.e. an increase in assessed value that has happened as a result of an improvement).
In General Motors the ARB interpreted sections 33 and 34 of the Act as prescribing different valuation dates than the general reassessment valuation date, being January 1, 2016. In other words, while properties in Ontario generally continue to be valued as of January 1, 2016, under the ARB's interpretation inGeneral Motors, if a property receives a supplementary or omitted assessment, those assessments will have a different valuation date other than the January 1, 2016 general reassessment valuation date.
In General Motors, the ARB observed that there are two valuation dates "implicitly referenced" in section 34:
- the date that construction of an improvement is completed; and
- the date that an improvement commences to be used.
The ARB did not, however, indicate what the valuation date is for omitted assessments made under section 33.
This interpretation is not entirely new. It harks back to the findings in National Car Rental (Canada) Inc. v Municipal Property Assessment Corporation, Region 15, 2022 CanLII 53352 (ON ARB):
"However, only s. 33 and s. 34 provide that current value may be determined based on a valuation day which follows the general reassessment valuation day prescribed by s. 19.2 of the Act." (National Car, para 229)
While this interpretation of sections 33 and 34 has been on the books for several years, it is only recently that the ARB's findings have become a real point of contention in assessment appeals. At the time of writing this article, we are aware of at least two proceedings where the ARB has scheduled motions on this "issue." In one instance, all parties to the assessment appeal proceedings agree that there is only one valuation day for all assessments made during the current assessment cycle, being January 1, 2016.
Multiple valuation dates: A new challenge for valuation?
The ARB's increasing shift towards recognizing multiple valuation days in the assessment cycle raises some important and complex questions about how properties are to be valued going forward, particularly when we are in the middle of the ninth year of what was supposed to be a four-year assessment cycle.
To illustrate some potential complications, consider the following scenario:
An office building is assessed at $30,000,000 for the 2017-2024 taxation years and valued as of the January 1, 2016 valuation date under section 19.2 of the Act. On January 1, 2025, the owner of the office building completes an improvement, triggering a supplementary assessment by the Municipal Property Assessment Corporation ("MPAC"). Under the rationale in General Motors, the improvement is to be valued as of January 1, 2025, whereas the balance of the office building is to continue being valued as of January 1, 2016.
This raises some significant questions:
- can MPAC value the components of a property according to different valuation dates?
- can equity be achieved if comparable properties are assessed using different valuation dates?
- does the Act truly contemplate numerous valuation dates within the same assessment cycle?
- once the roll is returned annually under section 36, do the valuation dates of the supplementary assessments reset to January 1, 2016 for the subsequent tax year?
We suspect that the answers to these questions will be definitively answered through the ARB's processes or possibly court proceedings in the near future.
Despite recent findings, MPAC's website continues to emphasize a uniform valuation date:
"[T]he fixed valuation date for 2025 remains January 1, 2016" and "[T]he 2025 assessment is what the property would have sold for on January 1, 2016 – in its current state and condition, including any major changes since then. Think of it as this property, selling on that date."
Whether the status quo will be upended and a new era of recognizing multiple valuations dates will be confirmed remains to be determined. Taxpayers that receive supplementary and omitted assessments should be aware of the potential for their property to be subject to multiple valuation dates if the assessment is appealed and proceeds to a hearing on the merits before the ARB. Supplementary or omitted assessments with recent valuation dates after January 1, 2016 could significantly increase tax liabilities.
As the property tax and assessment system continues to evolve, collaboration and clarity become ever more important – now is the time to engage, prepare, and lead the conversation.
This article was co-authored with Paul Grosman, Vice President, Ryan.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
