2018 Q3 tax calendar: Key deadlines for businesses and other employers

August 6, 2018

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. Contact us to ensure you’re meeting all applicable deadlines and to learn more about the filing requirements.

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.

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