2018 Q3 tax calendar: Key deadlines for businesses and other employers
Here are some of the key tax-related deadlines affecting businesses and other employers during the third quarter of 2018. Keep in mind that this list isn’t all-inclusive, so there may be additional deadlines that apply to you.
July 31
• Report income tax withholding and FICA taxes for second quarter 2018 (Form 941), and pay any tax due. (See the exception below, under “August 10.”)
• File a 2017 calendar-year retirement plan report (Form 5500 or Form 5500-EZ) or request an extension.
August 10
• Report income tax withholding and FICA taxes for second quarter 2018 (Form 941), if you deposited on time and in full all of the associated taxes due.
September 17
• If a calendar-year C corporation, pay the third installment of 2018 estimated income taxes.
• If 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.