October 16
If a calendar-year C corporation that filed an
automatic six-month extension: - File a 2016 income tax return (Form 1120) and pay any
tax, interest and penalties due.
- Make contributions for 2016 to certain
employer-sponsored retirement plans.
October 31
- Report income tax withholding and FICA taxes for third
quarter 2017 (Form 941) and pay any tax due. (See exception below.)
November 13
- Report income tax withholding and FICA taxes for third
quarter 2017 (Form 941), if you deposited on time and in full all of the
associated taxes due.
December 15
- If a calendar-year C corporation, pay the fourth
installment of 2017 estimated income taxes.