Employers - Social Security, Medicare, and withheld income tax. File form 941 for the second quarter of the current year. Deposit any undeposited tax. (If your tax liability is less than $2,500, you can pay it in full with a timely filed return.) If you have deposited the tax for the quarter in full and on time, you have until August 10 to file the return. Federal Unemployment Tax. Deposit the tax owed through June if more than $500.If you maintain an employee benefit plan, such as a pension, profit sharing, or stock bonus plan, file form 5500 or 5500-EZ for the previous calendar year. 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.