Here are some of the key tax-related deadlines affecting businesses and other employers during the fourth quarter of 2020. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you. Thursday, October 15 If a calendar-year C corporation that filed an automatic six-month extension: File a 2019 income tax return (Form 1120) and pay any tax, interest and penalties due. Make contributions for 2019 to certain employer-sponsored retirement plans. Monday, November 2 Report income tax withholding and FICA taxes for third quarter 2020 (Form 941) and pay any tax due. (See exception below under “November 10.”) Tuesday, November 10 Report income tax withholding and FICA taxes for third quarter 2020 (Form 941), if you deposited on time (and in full) all of the associated...