March 17 – S-Corporation Election
File Form 2553, Election by a Small Business Corporation, to choose to be treated as an S corporation beginning with calendar year 2013. If Form 2553 is filed late, S treatment will begin with calendar year 2015.
March 17 – Electing Large Partnerships
Provide each partner with a copy of Schedule K-1 (Form 1065-B), Partner’s Share of Income (Loss) From an Electing Large Partnership, or a substitute Schedule K-1. This due date is effective for the first March 15 following the close of the partnership’s tax year. The due date of March 15 applies even if the partnership requests an extension of time to file the Form 1065-B by filing Form 7004.
March 17 – Social Security, Medicare and Withheld Income Tax
If the monthly deposit rule applies, deposit the tax for payments in February.
March 17 – Non-Payroll Withholding
If the monthly deposit rule applies, deposit the tax for payments in February.
March 17 – Corporations
File a 2013 calendar year income tax return (Form 1120 or 1120-A) and pay any tax due. If you need an automatic 6-month extension of time to file the return, file Form 7004, Application for Automatic Extension of Time To File Certain Business Income Tax, Information and Other Returns, and deposit what you estimate you owe. Filing this extension protects you from late filing penalties but not late payment penalties, so it is important that you estimate your liability and deposit it using the instructions on Form 7004.