Mon Mar 15: Corporations: File Form 1120 for 2009 calendar year and pay any tax due. For automatic 6-month extension, file Form 7004 and deposit estimated tax.
Mon Mar 15: Employers: Deposit payroll tax for Feb if the monthly deposit rule applies.
Mon Mar 15: S Corporations: File Form 1120S for 2009 calendar year and pay any tax due. Furnish a copy of Sch. K-1 to each shareholder.
Mon Mar 15: File Form 2553 to elect S Corporation status beginning with calendar year 2010.
Wed Mar 17: Deposit payroll tax for payments on Mar 10-12 if the semiweekly deposit rule applies.
