Taxpayers using a fiscal calendar for income tax purposes (and whose calendar year began during 2021) are required to file a 2021 short year return no later than April 15th, 2022. Return calculations will need to be prorated accordingly. Going forward, fiscal filers must submit their CAT returns no later than the 15th day of the fourth month after the fiscal year ends. Taxpayers using a calendar year for federal income tax purposes will not be affected.