When Are S Corp Tax Returns Due? Federal & State Deadlines

An S corporation serves as a popular business structure, allowing profits and losses to pass directly to owners’ personal income without being subject to corporate tax rates. This pass-through taxation means the business itself typically does not pay federal income tax, but instead, shareholders report the income or losses on their individual tax returns. Understanding the specific tax return due dates for S corporations is important for business owners to ensure compliance and avoid potential penalties. Meeting these deadlines helps maintain the S corporation’s standing and facilitates proper financial reporting for all involved parties.

Federal S Corporation Income Tax Return Due Dates

Federal tax laws establish specific deadlines for S corporations to file their annual income tax returns with the Internal Revenue Service (IRS). For most S corporations operating on a calendar year, the Form 1120-S, U.S. Income Tax Return for an S Corporation, is due by March 15th. If this date falls on a weekend or holiday, the deadline shifts to the next business day. For instance, in 2025, the due date is March 17th.

S corporations can obtain an automatic six-month extension to file their Form 1120-S by submitting Form 7004. This extension typically pushes the filing deadline to September 15th for calendar-year filers. Filing an extension provides additional time to file the return, but it does not extend the deadline for paying any tax due.

S corporations that operate on a fiscal year, rather than a calendar year, have a different filing schedule. Their Form 1120-S is due on the 15th day of the third month following the close of their tax year. For example, an S corporation with a fiscal year ending on January 31st would have an April 15th due date. The same extension rules apply, allowing them to file Form 7004 by their original due date to extend their filing period by six months.

The timely filing of Form 1120-S is also important because it includes Schedule K-1, Shareholder’s Share of Income, Deductions, Credits, etc., for each shareholder. These Schedule K-1s report each shareholder’s portion of the S corporation’s income or loss, which they need to complete their personal income tax returns. Shareholders generally rely on receiving their K-1s in a timely manner to meet their individual tax obligations.

State S Corporation Tax Return Due Dates

While federal S corporation tax deadlines are consistent across the country, state-level filing requirements can vary significantly. Many states align their S corporation income tax return due dates with the federal March 15th and September 15th (for extended returns) deadlines. However, some states maintain different schedules for income tax returns, or they may impose other types of taxes with unique due dates.

States may levy various types of taxes on S corporations, such as income tax, franchise tax, or privilege tax, each potentially having its own filing deadline. These state-specific taxes often require separate forms and calculations. Therefore, relying solely on federal deadlines could lead to missed state obligations.

It is advisable for business owners to consult their specific state’s tax agency website or a qualified tax professional to ascertain the precise due dates for all applicable state S corporation tax returns. State rules for obtaining extensions can also differ from federal guidelines. Confirming these state-specific requirements is important to ensure full compliance and avoid penalties.

Consequences of Late Filing

Failing to file federal S corporation tax returns by the due date, including extensions, can result in penalties. The IRS imposes a failure-to-file penalty for Form 1120-S. This penalty is calculated on a per-shareholder, per-month basis, and it can accumulate for up to 12 months.

Separate penalties apply for the late payment of any tax due. While S corporations typically do not pay federal income tax directly, they may owe other taxes or have a tax liability in certain situations. A failure-to-pay penalty, often calculated as a percentage of the unpaid tax for each month or part of a month it remains unpaid, can be assessed in such cases.

States also have their own penalty structures for late filing and late payment of S corporation taxes. These state penalties can vary in amount and calculation method, often including interest charges on unpaid balances. Adhering to both federal and state deadlines is therefore important to avoid these financial repercussions, which can add up significantly over time.