Here are some of the key tax-related deadlines affecting businesses and other employers during the fourth quarter of 2021. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you. Contact us to ensure you’re meeting all applicable deadlines and to learn more about the filing requirements. Note: Certain tax-filing and tax-payment deadlines may be postponed for taxpayers who reside in or have a business in federally declared disaster areas.  Friday, October 15 If a calendar-year C corporation that filed an automatic six-month extension: File a 2020 income tax return (Form 1120) and pay any tax, interest and penalties due. Make contributions for 2020 to certain employer-sponsored retirement plans. Monday, November 1 Report income tax withholding and FICA taxes for third...