Thursday, March 15th 2018
S Corporations. File your 2017 calendar-year in come tax return (Form 1120-S) and pay any tax that is due. Provide each shareholder with a copy of Schedule K- 1 ( Form 1120-S), Shareholder's Share of Income, Deduction, Credits, etc., or a substitute Schedule K- 1. For an automatic six-month extension, file Form 7004.
S Corporation Election. File Form 2553, Election by a Small Business Corporation, by this date to be treated as an S corp beginning with calendar-year 2018. If you miss the deadline, the switch generally won't take effect until calendar-year 2019.
Partnerships (and LLCs treated as partnerships). File your 2017 calendar-year return (Form 1065). Provide each partner with a copy of Schedule K-1, Partner's Share of Income, Deduction, Credits, etc., or a substit u te Schedule K-1. For an automatic six-month extension, file Form 7004.
Employers. February 2018 payroll tax deposit is due if you're not on a semiweekly deposit schedule.