Something is filed by December 31 that estimates filing? - nothing for the S-Corp for federal purposes but maybe something for the state. generally, states have a franchise tax return/annual report (due dates vary) for a corporation but that mat not apply if it were an LLC that elected S-Corp status. may states impose a fee for being an LLC again due dates vary
W-2 by January 31st? - actually 2/1/21 because 1/31 is a Sunday
Schedule k by March 15th? yes but actually k-1 to shareholders
1120s by March 15th? yes
Federal and state return by March 15th - the only federal income tax return is the 1120s (as above) unless you elected a fiscal year other than one ending 12/31. some states require that a tax return be filed have a different due date than the federal and some of those impose an income tax on the S-Corp net income. others have no filing requirements.
you also have to file form 940 federal unemployment tax return. you may have state filing requirements for state unemployment. those are usually filed quarterly
Who Must File Form 940?
Except as noted below, if you answer “Yes” to either one
of these questions, you must file Form 940.
• Did you pay wages of $1,500 or more to employees in
any calendar quarter during 2019 or 2020?
• Did you have one or more employees for at least some
part of a day in any 20 or more different weeks in 2019 or
20 or more different weeks in 2020? Count all full-time,
part-time, and temporary employees.
If your business was sold or transferred during the year,
each employer who answered “Yes” to at least one
question above must file Form 940. However, don't
include any wages paid by the predecessor employer on
your Form 940 unless you’re a successor employer. For
details, see Successor employer under Type of Return,
later.
If you’re not liable for FUTA tax for 2020 because you
made no payments to employees in 2020, check box c in
the top right corner of the form. Then go to Part 7, sign the
form, and file it with the IRS.
If you won’t be liable for filing Form 940 in the future
because your business has closed or because you
stopped paying wages, check box d in the top right corner
of the form. For more information, see Final: Business
closed or stopped paying wages under Type of Return,
later.
these are the normal due dates. there is no telling if the IRS and/or state will automatically extend the due dates if the pandemic is still going on.
