October 2021 Business Due Dates
October 15 - Corporations
File a 2020 calendar year income tax return (Form 1120) and pay any tax, interest, and penalties due. This due date applies only if you timely requested an automatic 6-month extension by April 15.
October 15 - Social Security, Medicare and withheld income tax
October 15 - Nonpayroll Withholding
If the monthly deposit rule applies, deposit the tax for payments in September.
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