The S corporation deadline refers to the federal tax form 1120-S that all S corporations must file after three months and 15 days have passed since the end of the tax year. For example, an S corporation with a fiscal year end on July 31 will have to file form 1120-S until October 15 of the same year. For calendar years ending December 31, the deadline is March 15th.

S corporations are businesses that choose to pay taxes as shareholders for any revenue, debt, credit, or deduction purposes. They do not have to pay federal taxes, but they must still use federal tax form 1120-S to file their tax returns.

Filing and Reporting Employment Taxes

There are two forms that are used for reporting due taxes on employment: Form 941 and Form 940.

  • Form 941 is used quarterly to report any income from wages, tax withholdings on federal incomes, or tips. It also reports withheld taxes on Social Security or Medicare, and unemployment health insurance. The submission deadlines are every three months, on January 31, April 30, July 31, and October 31.
  • Form 940 is used every year to report taxes for federal unemployment. They are due when they exceed $500 for one trimester. It is due every year mad up until January 31, regardless of the date the payments were made.

An excise tax is specific to certain items, like gambling, gas, or tanning salons. Each one of the services and items that fall under this category has different forms and reporting periods for paying the tax. For example, excise taxes for communication, oil, gas air transports, or coal mining are reported four times every year using Form 720.

How to Make Federal Tax Payments

The most convenient way to make federal tax payments, for both taxpayers and the IRS, is by using the Electronic Federal Tax Payment System. An alternate way for S corporations is to make payments via bank wire transfer. The S corporation can employ a tax handler to make a direct payment on the company's behalf, but that usually implies an extra fee.

Tax returns are due three months and 15 days from the end of the company's fiscal year. In case the 1120-S tax returns for an S corporation are rejected by the IRS, the business has 10 days to work on the tax return and resend the file and it would still be considered as filed on time. A corporate extension's validity is six months and must be sent to the IRS while respecting the same deadline as the tax return.

Due Dates and Extension Deadlines

Single-member limited liability companies and sole proprietorships had until April 17, 2018 to file their tax returns for 2017. For the same year, partnership, multiple-member LLC, and S corporation returns were all due on March 15, 2018. The deadline for C corporations ending their fiscal year on December 31 was April 17, 2018. For C corporations with a fiscal year-end that is different from the calendar year, the tax return due date is the fourth month after the tax year.

The final deadline after an extension for partnerships and S corporations was September 15, 2018. C corporations are given an extra month, until October 15. Extension deadlines for other types of companies are October 16 for sole proprietors and single-member LLCs and September 17 for multi-member LLCs, partnerships, and S corporations.

If the tax return filing due day falls on weekends or holidays, it is moved to the next working day. For example, this year the due date for filing corporate tax returns using Form 1120 should have been April 15, three months and 15 days from the beginning of the calendar year. However, since April 15 fell on a Sunday and on Monday, April 16 a holiday took place in the District of Columbia, the appointed deadline for filing the form was Tuesday, April 17.

An automatic two-month extension is given to expats living in other countries, making the deadline fall on June 15. Sole proprietors and single-members LLC have the same due dates as the people running them, as all income is passed through those specific persons.

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