AUGUST 2018

August 10

Employers. For Social Security, Medicare, and withheld income tax, file Form 941 for the second quarter of 2018. This due date applies only if you deposited the tax for the quarter in full and on time.

 

August 15

Employers. For Social Security, Medicare, withheld income tax, and nonpayroll withholding, deposit the tax for payments in July if the monthly rule applies.

 

SEPTEMBER 2018

 

September 17

Individuals. If you are not paying your 2018 income tax through withholding (or will not pay in enough tax during the year that way), pay the third installment of your 2018 estimated tax. Use Form 1040-ES.

Employers. For Social Security, Medicare, withheld income tax, and nonpayroll withholding, deposit the tax for payments in August if the monthly rule applies.

Corporations. Deposit the third installment of estimated income tax for 2018. Use the worksheet Form 1120-W to help estimate tax for the year.

Partnerships. File a 2017 calendar-year return (Form 1065). This due date applies only if you timely requested an automatic six-month extension. Provide each partner with a copy of his or her final or amended Schedule K­1 (Form 1065) or substitute Schedule K­1.

S corporations. File a 2017 calendar-year income tax return (Form 1120S) and pay any tax, interest, and penalties due. This due date applies only if you timely requested an automatic six-month extension. Provide each shareholder with a copy of Schedule K-1 (Form 1120S) or a substitute Schedule K-1.