Important dates for corporations





You have 90 days from the date of the notice of assessment or reasessment to file a formal objection. See resolving disputes for more information.

Refund interest

When we refund or apply an overpayment, we pay refund interest from certain dates.


We will calculate late payment interest, refund interest, or both, for the carryback from 30 days after certain dates. See Effect of a carryback on interest for more information.


Within 45 days of incorporation, you should receive a notice confirming your business number (BN) and summary of accounts including your corporation income tax program account.

Fiscal period

The corporation's tax year is its fiscal period. See Determining your corporation's tax year for more information.

Tax year-end

A corporation can use a calendar year for the GST/HST account or use the same fiscal period as the corporation income tax account.

To change your tax year-end, see Change of fiscal period.

Keeping records

  • Keeping records – Information you need to know about maintaining your records.
  • Retention period – You have to keep your business records for 6 years.
  • Early destruction – In some cases, we may give you permission to destroy your books and records before the six years have passed.

Related topics

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