When is an S-Corp tax return due? The annual tax return due date is typically March 15 for many businesses. However, your due date may be different, depending on when your fiscal tax year ends. In addition, some S-Corps pay quarterly taxes, which have other due dates.

Deadlines for S-Corp Tax Returns

S-Corporations are responsible for filing informational income tax returns annually. They may also have to file a variety of other forms, such as payroll tax forms. Due dates that fall on Saturday, Sunday, or federal holidays will extend to the next weekday.

An S-Corporation has a due date of the 15th day of the third month after its tax year ends in which to file its yearly return. For most companies, this due date is March 15 since their fiscal year ends on December 31. However, if an S-Corp ends its fiscal year on August 31, its return is due by November 15 that same year.

The business must report all financial activity on form 1120S. It must also attach a Schedule K-1 for each company shareholder, or owner. Schedule K-1s report a shareholder's portion of the business's taxable income. Shareholders then report this information on their individual tax returns.

If an S-Corp can't meet the March 15 deadline, it can file form 7004 for an automatic six-month extension. A due date of September 15 is only applicable when the six-month extension is obtained.

For S-Corps that have dissolved, they must file a return by the same deadline after the dissolution date, or the 15th day of the third month after dissolution.

Unlike the S-Corp itself, company shareholders have the same deadline as other individual taxpayers for paying their share of taxes on the company's income, which is typically April 15 of each year.

While an S-Corporation doesn't pay federal taxes, the state the business is registered in may require it to pay state taxes.

Deadlines for Quarterly Returns and Unemployment Filing

If your S-Corp pays salaries to employees, your company must withhold the following from employee paychecks:

  • Federal income tax 
  • Medicare tax 
  • Social Security 

Your S-Corp must file form 941 every quarter to report withholding amounts. Due dates for form 941 are as follows: 

  • January 31
  • April 30
  • July 31 
  • October 31

Along with income tax withholding, form 941 also reports tips, quarterly wages, COBRA credits, and adjustments to Medicare taxes and Social Security.

Your S-Corp might also be responsible for filing a yearly Federal Unemployment Tax Return on form 940. The purpose of form 940 is to report the amount of wages for which your S-Corp owes unemployment taxes. Federal unemployment taxes are also known as FUTA. When these payments are more than $500 in a quarter, they're due.

You'll generally also have to file form 940 if one of the following occurs: 

  • You pay at least $1500 in wages in a quarter. 
  • You have at least one employee who works at least part of the day for 20 weeks or more.

Your deadline for filing form 940 is January 31. If you pay the entire tax on time, the IRS gives you a deadline that's as late as February 10.

Many forms can be filed later than the usual deadlines if you file for an extension, which is typically up to six months from the original due date.

If your S-Corp doesn't file its annual tax return by deadline or extended deadline, the IRS will impose penalties. Fines begin at $195 for every month or portion of the month the return is late. It's then multiplied by the number of company shareholders.

If your S-Corp files form 941 after the due date and you have an unpaid tax balance, the IRS may assess a 5% penalty. This penalty will be assessed up to a maximum of 25%. If you file form 940 after the deadline, similar penalties apply.

Probably the most important tax return due date is the one for yearly returns. However, even late filing on quarterly returns can have costly consequences. As a business owner, it's important to be organized, particularly where your finances are concerned. By filing forms on time, you avoid what could turn out to be substantial penalties. 

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