Whether adjustments can be made to corporate tax returns in Canada is dependent upon the type of corporation and year of the tax return. If at the end of the tax year a corporation was considered a Canadian-controlled private corporation (CCPC), they can adjust their tax returns within three years from the date of the mailing of the original Notice of Assessment, while Non-Canadian-controlled private corporations (Non-CCPC) have four years.
Determine the address of the appropriate tax center. This is contingent upon the territory or province and the city where the corporation is located.
Write a letter to the appropriate tax center stating the reason for the requested reassessment (adjustment). Include supporting documentation, such as revised schedules or financial statements. State the corporation's name, tax year, and Business Number (BN) in the letter. Do not include the bar code sheet and full T2 return with the letter.
File the appropriate schedule (Schedule 4, 21, 31, 37, or 42) if the requested change to the corporate tax return is either a tax credit or the carry-back of a loss. Mail this schedule with the related T2 tax return. Alternatively, the schedule can be mailed separately to the corporation's tax center.
Pay additional tax that is expected to be due upon the adjustment of the return in order to avoid interest charges. File Form RC159, Amount Owing Remittance Voucher with the payment. State on the voucher that it is an advance deposit. Also include on the voucher the corporation's Business Number (BN) and tax year end to which the deposit is associated. If more than one tax year is being adjusted, identify clearly the advance payments and associated years.