September 2018 Business Due Dates

September 17 - S Corporations

File a 2017 calendar year income tax return (Form 1120S) and pay any tax due. This due date applies only if you requested an automatic 6-month extension. Provide each shareholder with a copy of K-1 (Form 1120S) or a substitute Schedule K-1.

September 17 - Corporations 

Deposit the third installment of estimated income tax for 2018 for calendar year

September 17 -  Social Security, Medicare and withheld income tax

If the monthly deposit rule applies, deposit the tax for payments in August.

September 17 - Nonpayroll Withholding

If the monthly deposit rule applies, deposit the tax for payments in August.

September 17 - Partnerships

File a 2017 calendar year return (Form 1065). This due date applies only if you were given an additional 5-month extension. Provide each partner with a copy of K-1 (Form 1065) or a substitute Schedule K-1.

September 17 - Electing Large Partnerships 

File a 2017 calendar year return (Form 1065-B). This due date applies only if you were given a 6-month extension. March 15 was the due date for furnishing Schedules K-1 or substitute Schedule K-1 to the partners.



Share this article...

Want tax & accounting tips and insights?

Sign up for our newsletter.

I confirm this is a service inquiry and not an advertising message or solicitation. By clicking “Submit”, I acknowledge and agree to the creation of an account and to the and .

Get in Touch with AllTax Accounting

You can count on us for professional, timely and reliable tax and accounting services. If you’re ready to get started, just fill out this form and we’ll be in touch.

100 West Road, Suite 300
Towson, Maryland 21204
I confirm this is a service inquiry and not an advertising message or solicitation. By clicking “Submit”, I acknowledge and agree to the creation of an account and to the and .
By checking this box, I agree to receive Text messages about account notifications from AllTax Accounting at the phone number provided above. The SMS frequency may vary. Message and data rates may apply. Text HELP to (443) 406-6441 for assistance. Reply STOP to opt out of receiving SMS messages from AllTax Accounting. You will receive no further SMS communication. For more information, please refer to our Privacy Policy and SMS Terms and Conditions on our website.
AllTax Accounting Hello there! How can we help?
Welcome to Taxbot. Your smart tax assistant, simplifying tax deductions and maximizing returns.
Please fill out the form and our team will get back to you shortly The form was sent successfully