Waiver of assessment period
We may assess or reassess your return within six years of the delivery date of your return. For example, if we receive the tax return by mail, the date of delivery is the date the envelope is postmarked.
However, the six-year assessment period doesn’t apply, and you can be assessed or reassessed tax at any time, if you:
- Never filed the tax return
- Made a misrepresentation or committed fraud in filing the tax return or providing information
- Filed a waiver within the assessment period
You may choose to voluntarily extend the six-year assessment period in connection with specific issue(s):
- To allow enough time for an adequate resolution of an audit
- To improve the accuracy of an assessment by allowing additional time for further discussion and collection of information before an assessment is issued
Once you waive the assessment period, we may assess or reassess tax until 6 months after the waiver has been revoked.
To waive the assessment period, complete the Waiver of Assessment Period (FIN 27) (PDF). You or your authorized representative must sign and file the completed form within the six-year assessment period. To authorize a third party representative, complete an Authorization or Cancellation of a Representative (FIN 146) (PDF).
You can send the forms by:
To revoke the waiver, complete the Notice of Revocation of Waiver (FIN 525) (PDF). You can send the form by:
The notice of revocation will take effect six months after the date it’s filed. The notice cannot be cancelled once it has been filed.