The March tax filing deadline for S corporations and partnerships is approaching quickly. Each year, business owners are caught off guard by IRS penalties for filing late, even when no tax is owed at the entity level. A quick check now can help you avoid penalties and last-minute stress.
March 16, 2026 is the tax filing deadline for 2025 calendar-year S corporations and partnerships. While this filing does not require a tax payment at the business level, missing the deadline can result in significant penalties and create complications for business owners’ personal tax returns.
If you are a shareholder in an S corporation or a partner in a partnership, understanding what is required and why this deadline matters can help you avoid unnecessary costs and stress this tax season.
Even when no tax is due, the IRS imposes penalties for late-filed S corporation and partnership returns.
For 2025 returns, the penalty is $255 per shareholder or partner, per month or part of a month, for up to 12 months.
That means a return filed just one day late could still trigger a full month’s penalty. For example, if a married couple jointly owns an S corporation and the return is filed on March 16 instead of March 15, the penalty could total $510, even though no tax is owed at the entity level.
These penalties add up quickly, especially for businesses with multiple owners.
S corporations and partnerships are pass-through entities, meaning business income is reported on the owners’ individual tax returns using Schedule K-1s.
If your business return is filed late or extended:
This can compress your personal filing timeline and increase the risk of underpayment penalties if estimates are not made correctly by the April 15 individual filing deadline.
If you have not yet filed your S corporation or partnership return, there is still time to act.
Aim to file your business return on or before March 16. Filing on time helps avoid penalties and ensures you receive K-1s early enough to prepare your personal return.
If your return will not be ready by the deadline, file an extension by March 16. This gives you an additional six months to file the business return. Remember, taxes for pass-through businesses are paid on your individual return, not with the extension.
If your business return is extended, be prepared for the possibility that your personal return may also need to be extended. You should still estimate your 2025 tax liability and make any required payment by April 15.
If your business is penalized for filing late, you may be able to request penalty abatement. This is especially important if your individual tax return and payment were filed on time. In many cases, penalties can be reduced or removed when reasonable cause is demonstrated.
If you have not yet filed your 2025 S corporation or partnership return or are unsure whether an extension makes sense for your situation, now is the time to take action.
Contact Alloy Silverstein to get help filing, extending, or coordinating your business and personal tax planning. Our team can help you stay compliant, minimize penalties, and keep your tax season on track.
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