January 15th

Last estimate for prior year (2009)

February 1st

W2 and 1099 due to recipients

March 1st

W3 and W2 Copy A due to Social Security, 1096 and Copy A to IRS

March 15th

1120 and 1120S or automatic extension good for 6 months
2553 election to be classified a small business

March 31st

Electronic W2’s

April 15th

1040 or can extend for 6 months
1065 or can extend for 5 months
First 1040 estimated payment due for 2010

June 15th

Second 1040 estimated payment due for 2010

August 2nd

5500’s due

September 15th

Third 1040 estimated payment due for 2010
1120, 1120s and 1065 due with extension

October 15th

1040 due with extension

January 15th, ‘11

Fourth and final 1040 estimated tax payment due