Corporations – File a 2009 calendar year income tax return (Form 1120 or 1120-A) and pay any tax due. This due date applies only if you made a timely request for an automatic 6-month extension.

S corporations – File a 2009 calendar year income tax return (Form 1120S) and pay any tax due. This due date applies only if you made a timely request for an automatic 6-month extension. 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 2010. A worksheet, Form 1120-W, is available to help you make an estimate of your tax for the year.

Employers – Nonpayroll withholding. If the monthly deposit rule applies, deposit the tax for payments in August.

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

Employers – Federal unemployment tax. Deposit the tax owed through June if more than $500.

Employers – If you maintain an employee benefit plan, such as a pension, profit sharing, or stock bonus plan, file Form 5500 or 5500-EZ for calendar year 2009. If you use a fiscal year as your plan year, file the form by the last day of the seventh month after the plan year ends.

Certain Small Employers – Deposit any undeposited tax if your tax liability is $2,500 or more for 2010 but less than $2,500 for the second quarter.

Employees Who Work for Tips – If you received $20 or more in tips during July, report them to your employer. You can use Form 4070.

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