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, 2018.

March 12

Employees who work for tips – If you received $20 or more in tips during February, report them to your employer. You can use Form 4070.

March 15

Employers – Nonpayroll withholding. If the monthly deposit rule applies, deposit the tax for payments in February.

Employers – Social Security, Medicare, and withheld income tax. If the monthly deposit rule applies, deposit the tax for payments in February.

Partnerships – File a 2017 calendar year income tax return (Form 1065). Provide each partner with a copy of their Schedule K-1 (form 1065-B) or substitute Schedule K-1. To request an automatic 6-month extension of time to file the return, file Form 7004. Then file the return and provide each partner with a copy of their final or amended (if required) Schedule K-1 (Form 1065) by September 17.

S Corporations – File a 2017 calendar year income tax return (Form 1120S) and pay any tax due. Provide each shareholder with a copy of Schedule K-1 (Form 1120S), Shareholder’s Share of Income, Credits, Deductions, etc., or a substitute Schedule K-1. If you want an automatic 6-month extension of time to file the return, file Form 7004 and deposit what you estimate you owe.

Electing large partnerships – File a 2017 calendar year return (Form 1065-B). Provide each partner with a copy of Schedule K-1 (Form 1065-B), Partner’s Share of Income (Loss) From an Electing Large Partnership. This due date applies even if the partnership requests an extension of time to file the Form 7004.

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.

April 2

Electronic filing of Forms 1097, 1098, 1099, 3921, and 3922 – File Forms 1097, 1098, 1099, 3921, and 3922 with the IRS (except a Form 1099-MISC reporting nonemployee compensation). This due date applies only if you file electronically. Otherwise, see February 28. The due date for giving the recipient these forms generally remains January 31.

Electronic Filing of Form W-2G – File copies of all the Form W-2G (Certain Gambling Winnings) you issued for 2017. This due date applies only if you electronically file. Otherwise, see February 28. The due date for giving the recipient these forms remains January 31.

Electronic Filing of Forms 8027 – File copies of all the Forms 8027 you issued for 2017. This due date applies only if you electronically file. Otherwise, see February 28.

Electronic Filing of Forms 1094-C and 1095-C and Forms 1094-B and 1094-B – If you’re an applicable Large Employer, file electronic forms 1094-C and 1095-C with the IRS. For all other providers of essential minimum coverage, file electronic Forms 1094-B and 1095-B with the IRS. Otherwise, see February 28.