March 2018 Business Due Dates

March 1 - Farmers and Fishermen File your 2017 income tax return (Form 1040) and pay any tax due. However, you have until April 17 to file if you paid your 2017 estimated tax by January 16, 2017. March 15 - Partnerships File a 2017-calendar year return (Form 1065). Provide each partner with a copy of Schedule K-1 (Form 1065), Partner’s Share of Income, Deductions, Credits, etc., or a substitute Schedule K-1. If you want an automatic 6-month extension of time to file the return and provide Schedules K-1 or substitute Schedules K-1 to the partners, file Form 7004. Then, file Form 1065 and provide the K-1s to the partners by September 17. March 15 - 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 2018. If Form 2553 is filed late, S treatment will begin with calendar year 2019.

March 15 - S-Corporations File a 2017-calendar year return (Form 1120S). Provide each shareholder with a copy of Schedule K-1 (Form 1120S Shareholder’s Share of Income, Deductions, Credits, etc., or a substitute Schedule K-1. If you want an automatic 6-month extension of time to file the return and provide Schedules K-1 or substitute Schedules K-1 to the shareholders, file Form 7004. Then, file Form 1120S and provide the K-1s to the shareholders by September 17.

March 15 - Electing Large Partnerships File a 2017-calendar year return (Form 1065-B) and 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 applies for K-1s even if the partnership requests an extension of time to file the Form 1065-B by filing Form 7004. March 15 - Social Security, Medicare and Withheld Income Tax If the monthly deposit rule applies, deposit the tax for payments in February. March 15 - Non-Payroll Withholding If the monthly deposit rule applies, deposit the tax for payments in February.