September 2020 Business Due Dates

September 15 - S Corporations

File a 2019 calendar year income tax return (Form 1120-S) 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 1120-S) or a substitute Schedule K-1.

September 15 - Corporations 

Deposit the third installment of estimated income tax for 2020 for calendar year

September 15 -  Social Security, Medicare and Withheld Income Tax

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

September 15 - Nonpayroll Withholding

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

September 15 - Partnerships

File a 2019 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 30 - Fiduciaries of Estates and Trusts

File a 2019 calendar year return (Form 1041). This due date applies only if you were given an extension of 5 1/2 months. If applicable, provide each beneficiary with a copy of K-1 (Form 1041) or a substitute Schedule K-1.




Share this article...

Want our best tax and accounting tips and insights delivered to your inbox?

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 .
I consent to receive SMS messages

Our Offices

Our expertise is widespread and we have multiple office locations to make it convenient for you to get help. You can find us at:

Oregon Office

4545 SW 96th Ave
Beaverton, Oregon 97005
Monday through Friday:
9am to 5pm and by appointment

April-December
Monday through Thursday
10am to 2pm

Connecticut Office

P.O. Box 271356
West Hartford, Connecticut 06127
By Appointment Only

Idaho Office

2020 Blaine St.
Caldwell, Idaho 83605
Monday through Friday:
9am to 5pm and by appointment

April-December
Monday through Thursday
10am to 2pm