Filing an extension for your S corporation gives you additional time to complete your business tax return, but it does not mean putting taxes aside until September.
If you filed an extension for a calendar-year S corporation’s 2025 return, the extended filing deadline is September 15, 2026.
Keep in mind that an extension gives you more time to file, not more time to pay. Any taxes owed were still due by the original deadline.
The months between the original filing deadline and September provide an opportunity to clean up your financial records, address missing information, and prepare both your business and personal tax filings.
Step 1: Make Sure Your Bookkeeping Is Current
Your tax return is only as reliable as the financial information supporting it.
Review your bookkeeping and make sure transactions are properly recorded and accounts are reconciled.
Look closely at:
- Bank accounts
- Business credit cards
- Payroll
- Loans
- Equipment purchases
- Owner contributions
- Shareholder distributions
- Business expenses
If something does not look right, address it before your CPA begins finalizing the return.
Step 2: Gather Missing Tax Documents
An extension is useful when information was unavailable by the original deadline. Use the additional time to track down anything that is still missing.
Depending on your business, this could include payroll reports, loan statements, asset purchase information, prior-year documents, corrected tax forms, and financial statements.
Organizing this information early can reduce back-and-forth later.
Step 3: Review Shareholder Activity
S corporation owners should pay particular attention to shareholder-related transactions.
For example, distributions, contributions, loans between shareholders and the business, and compensation can have tax implications.
Rather than trying to determine the tax treatment yourself, make sure these transactions are clearly identified for your CPA.
Step 4: Remember Your Personal Return
An S corporation is generally a pass-through entity. Shareholders receive a Schedule K-1 showing their share of certain tax items.
That means your business return and personal return are closely connected.
If you extended your personal return as well, completing the S corporation return provides information needed to finish your individual return.
For 2025 individual income tax returns on a valid extension, the deadline is generally October 15, 2026.
Step 5: Start Thinking About 2026
While your CPA is completing the 2025 return, you are already well into the 2026 tax year.
This creates an opportunity to compare last year’s results with your current performance.
Has revenue increased? Have expenses changed? Did you hire employees? Purchase equipment? Increase shareholder wages or compensation? Make major investments?
Changes like these can affect your 2026 tax planning.
Instead of viewing the extended return as purely backward-looking, use it to start a conversation about what is happening now.
Frequently Asked Questions
Does an S corporation extension give me six more months?
Generally, yes. A valid extension gives a calendar-year S corporation six additional months to file its return. For the 2025 tax year, the original federal deadline was March 16, 2026, and the extended deadline is September 15, 2026.
When is my extended S corporation return due in 2026?
For a calendar-year S corporation filing its 2025 return, the extended deadline is generally September 15, 2026.
Do I need my S corporation return before filing my personal return?
S corporation shareholders generally need information from their Schedule K-1 to accurately complete their individual income tax returns.
Should I wait until September to contact my CPA?
No. Getting records and questions to your accounting team earlier can make the filing process more efficient.
Filed an extension? Make the extra time count. Contact DDC to get organized, complete your return, and start looking ahead to 2026.