There are three main tax-related deadlines affecting businesses and other employers during the third quarter of 2018: July 31st, August 10th, and September 17th.
- Report any income tax withholding and FICA taxes for second quarter 2018 (Form 941), and pay any tax that is due. (See the exception below, under “August 10th.”)
- File a 2017 calendar-year retirement plan report (Form 5500 or Form 5500-EZ) or ask for an extension.
- If you deposited on time and fully paid all associated taxes, report income tax withholding and FICA taxes for second quarter 2018 (Form 941).
- If you are a calendar-year C corporation, pay the third portion of your 2018 estimated income taxes.
- If you are a calendar-year S corporation or partnership that filed an automatic six-month extension:
- File a 2017 income tax return (Form 1120S, Form 1065 or Form 1065-B) and pay any tax, interest and penalties due.
- Make contributions for 2017 to certain employer-sponsored retirement plans.