Individuals - Make a payment of your 2009 estimated tax if you are not paying your income tax for the year through withholding (or will not pay in enough tax that way). Use Form 1040-ES. This is the third installment date for estimated tax in 2009.

Corporations - File a 2008 calendar year income tax return (Form 1120 or 1120-A) and pay any tax due. This due date applies only if you timely requested an automatic 6 month extension. Otherwise, see March 16.

S Corporations - File a 2008 calendar year income tax return (Form 1120S) and pay any tax due. This due date applies only if you timely requested an automatic 6 month extension. Otherwise, see March 16. Provide each shareholder with a copy of Schedule K-1 (Form 1120S) or a substitute Schedule K-1.

Corporations - Deposit the third installment of estimated income tax for 2009. A worksheet, Form 1120-W, is available to help you make an estimate of your tax for the year.

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

Employers - Nonpayroll Withholding. If the monthly deposit rule applies, deposit the tax for payments in August.