September 2021 Business Due Dates

September 15 - S Corporations

File a 2020 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 their Schedule K-1 (Form 1120-S) or a substitute Schedule K-1.

September 15 - Corporations 

Deposit the third installment of estimated income tax for 2021 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 2020 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 2020 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...

Sign up for our newsletter.

Each month, we will send you a roundup of our latest blog content covering the tax and accounting tips & insights you need to know.

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 .

We care about the protection of your data.

Get in Touch with Quantum Tax Consultants

Have any question? Just fill out this form and we’ll be in touch. Get a free initial consultation for new clients.

28 Broadway
Passaic, New Jersey 07055
We are open from
M-F: 9am-6pm
Saturday: 9am-3pm
Sundays: 10am-2pm (EST)
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 and agree with the