2011
February 28 – Annual 1096 and 1099 forms must be filed with the IRS.
March 15 – 2010 income tax returns for 1120, 1120S, Forms 5452, 5471, 1042 and 1042S due.
April 18 – 2010 income tax returns for Individuals, trusts and estates and partnerships due.
May 15 – Calendar year exempt organizations, private foundations, Form 5498 due.
June 15 – Non-resident alien income tax returns due; estimated tax payments for calendar year individuals, trusts, estates and corporations due.
July 31 – Employer’s taxes due.
September 15 – Estimated tax payments for calendar year individuals, trusts, estates and corporations due. Final due date for corporations, trusts and partnerships.
October 15 – Final due date for individuals to file IRS income tax returns.
October 31 – Employer taxes due.
December 15 – Estimated taxes for corporations due.
January 15, 2012 – Estimated tax payments for individuals, trusts, estates and corporations due.