Filing a tax extension can give your business additional time to complete its tax return, but it doesn’t mean you can put your taxes out of mind until next year.
For many businesses that extended their 2025 tax returns, the new filing deadline is approaching. Depending on the type of business and tax return, that deadline may be September 15 or October 15, 2026.
If you filed an extension, now is the time to make sure your financial records are complete, your tax documents are organized, and your tax professional has everything needed to finish the return.
Here are seven things business owners should do before their extended tax deadline.
1. Confirm Your Business Tax Extension Deadline
The first step is knowing exactly when your extended return is due.
For many calendar-year businesses, the extended deadline is September 15, 2026, while certain individual and other returns are generally extended until October 15, 2026.
The deadline depends on the type of tax return your business files.
Common examples include:
- Partnerships and multi-member LLCs: Generally due September 15 after an extension
- S corporations: Generally due September 15 after an extension
- C corporations: Generally due October 15 after an extension for calendar-year corporations
- Sole proprietors: Business income is generally reported on the owner’s individual return, which is generally due October 15 after an extension
Because filing requirements can vary depending on the entity’s tax year and circumstances, business owners should confirm their specific deadline with their tax professional.
Don’t assume that filing an extension gives every business the same additional amount of time.
2. Remember: An Extension Gives You More Time to File, Not More Time to Pay
One of the most important things to understand about a tax extension is that it generally extends the filing deadline—not the deadline for paying taxes owed.
If your business or its owners owe taxes, those taxes generally need to have been paid by the original tax deadline to avoid potential interest and penalties.
For example, if your business expects to owe additional taxes, waiting until September or October to make the payment could result in additional costs.
Your tax professional can help determine whether additional payments are needed and how much should be paid.
3. Make Sure Your Financial Statements Are Complete
Your tax return is only as accurate as the financial information behind it.
Before your tax preparer completes the return, make sure your books are up to date and your financial statements are accurate.
At a minimum, review:
- Profit and loss statement
- Balance sheet
- Bank accounts
- Credit card accounts
- Accounts receivable
- Accounts payable
- Loans and other liabilities
- Fixed assets
- Owner distributions and contributions
Pay particular attention to unreconciled accounts, unusual transactions, and transactions that haven’t been properly categorized.
Cleaning up these issues before tax preparation can make the process faster and reduce the amount of time your tax professional needs to spend researching your books.
4. Gather Missing Tax Documents
Your accountant may need more than your standard financial statements to complete the return.
Depending on your business, gather documents related to:
- Equipment and other major asset purchases
- Business loans
- Vehicle expenses
- Payroll
- Contractor payments
- 1099s
- Charitable contributions
- Insurance
- Retirement plans
- Ownership changes
- New business entities
- Real estate transactions
- Investment activity
If your business has international ownership, foreign accounts, or transactions with foreign-related parties, additional information may also be required.
Don’t wait for your tax preparer to discover missing information during the final weeks before the deadline.
5. Review Your Business for Changes That Could Affect Your Return
Your tax professional needs to know what changed during the year.
Significant business changes can affect how your return is prepared and what information needs to be reported.
Consider whether your business:
- Bought or sold significant assets
- Took on new debt
- Added or removed owners
- Changed its business structure
- Acquired another company
- Sold part of the business
- Opened or closed locations
- Began operating in another state
- Started doing business internationally
- Hired independent contractors
- Made significant investments
Providing this information early gives your tax professional more time to determine whether additional tax forms or filings are required.
6. Don’t Overlook Estimated Tax Payments
Filing your tax return and making your estimated tax payments are separate issues.
Depending on your business structure, income may pass through to the owners, who may be responsible for making estimated individual tax payments.
Other businesses may have their own estimated tax obligations.
Before the extended deadline, confirm:
- What taxes have already been paid
- Whether additional payments are expected
- Whether quarterly estimated payments are current
- Whether your projected tax liability has changed
A business that experienced significant growth during 2025 may have a larger tax liability than originally expected.
7. Don’t Wait Until the Deadline
An extension may provide additional time, but using all of that time doesn’t necessarily make the process easier.
Waiting until the last few weeks can create problems if:
- Your books aren’t reconciled
- Documents are missing
- Your tax return requires additional research
- International reporting forms are needed
- Your tax liability is larger than expected
- Your accountant needs clarification
- Corrections need to be made to your financial statements
Giving your tax professional complete information early creates more time to identify and resolve issues.
What Happens If You Miss Your Extended Tax Deadline?
Missing an extended filing deadline can result in penalties and interest, depending on the circumstances and the type of return involved.
The consequences can be particularly significant when a business owes taxes or fails to submit required information returns.
For that reason, business owners should not treat the extended deadline as a suggestion.
If you realize you may not be able to meet the deadline, contact your tax professional as soon as possible. They can help you understand your options and determine what steps should be taken.
Business Tax Extension Checklist
Use this checklist to make sure you’re ready for your extended deadline:
☐ Confirm your exact extended filing deadline
☐ Make sure your books are current
☐ Reconcile bank and credit card accounts
☐ Review your profit and loss statement
☐ Review your balance sheet
☐ Gather missing tax documents
☐ Provide information about major business changes
☐ Review equipment and other asset purchases
☐ Confirm estimated tax payments
☐ Identify any international activity or ownership
☐ Respond to your tax preparer’s questions
☐ Submit all requested information before the deadline
How Organized Financial Statements Can Make Tax Preparation Easier
Tax preparation starts with accurate financial information.
When financial statements are incomplete or disorganized, tax professionals may have to spend additional time:
- Investigating transactions
- Reconciling accounts
- Correcting bookkeeping errors
- Requesting missing documentation
- Determining how transactions should be classified
- Identifying potential deductions
That additional work can make tax preparation more time-consuming and potentially more expensive.
Keeping your accounting records organized throughout the year can help make the tax filing process more efficient while giving business owners a clearer picture of their financial performance.
When to Get Help With Your Business Tax Return
If you’re approaching your extended deadline and your books aren’t ready, don’t wait until the last minute to get help.
An accounting and advisory team can help ensure that your financial statements are accurate, accounts are reconciled, and necessary information is organized before the tax return is prepared.
At P&W Associates, our outsourced accounting, controller, and tax services help businesses maintain organized financial records throughout the year—not just when tax deadlines approach.
By keeping your books current and your financial information organized, you can make tax preparation easier while gaining better financial visibility throughout the year.
Frequently Asked Questions
What is the business tax extension deadline?
The deadline depends on the type of business and tax return. For many calendar-year partnerships and S corporations, the extended deadline is September 15. Certain calendar-year C corporations and individual returns generally have an October 15 extended deadline.
Does a tax extension give my business more time to pay?
Generally, no. A tax extension typically provides additional time to file the return, but taxes owed are generally still due by the original payment deadline.
What happens if I miss my business tax extension deadline?
You may face late-filing penalties, interest, or other consequences depending on the type of return and your circumstances. Contact your tax professional immediately if you think you may miss the deadline.
Should my books be completed before I send information to my tax preparer?
Yes. Accurate, reconciled financial statements make it easier for your tax professional to prepare the return and can reduce the time spent resolving accounting issues.
Can an accounting firm help prepare my books for tax filing?
Yes. An outsourced accounting or controller team can help keep financial statements current, reconcile accounts, organize documentation, and prepare financial information for your tax professional.
Don’t Wait Until the Extended Deadline
A tax extension gives business owners more time, but that time is most valuable when it’s used to get organized.
Confirm your deadline, make sure your financial statements are complete, gather missing documents, review estimated payments, and communicate with your tax professional well before the filing date.
Taking these steps now can help prevent last-minute surprises and make the tax filing process significantly smoother.
P&W Associates provides outsourced accounting, controller, tax, and advisory services to help business owners maintain accurate financial records and stay prepared throughout the year. If your business needs help getting its books ready for tax filing, our team can help.
