LLC or S-Corp on Extension? What to Review Before the September 15 Tax Deadline

If you own an LLC or S-Corporation and your 2025 business tax return is on extension, the September 15 filing deadline is approaching.

For many calendar-year S-Corporations and multi-member LLCs taxed as partnerships, September 15 is the extended federal filing deadline. The additional time provided by an extension can be valuable, particularly when bookkeeping needs to be completed or financial information is still being gathered.

However, an extension should also be an opportunity to make sure the underlying business records are accurate before the return is filed.

For small-business owners, this is especially important because the business return often directly affects the owner's individual tax return.

Here are several areas worth reviewing before filing your extended business return.

Make Sure You Know How Your LLC Is Taxed

One area that sometimes creates confusion is the tax treatment of an LLC.

An LLC is a legal business structure, but it does not automatically determine how the business is taxed. Depending on the circumstances, an LLC may be taxed as a sole proprietorship, partnership, S-Corporation, or C-Corporation.

For example, a multi-member LLC is commonly taxed as a partnership unless another tax election has been made. An LLC may also elect to be taxed as an S-Corporation.

Knowing your tax classification is important because it determines which tax return is filed and can also affect payroll, owner compensation, distributions, and other tax considerations.

Make Sure Your Bookkeeping Is Complete

Accurate bookkeeping is the foundation of a business tax return.

Before preparing the return, your accounting records should be reasonably complete and up to date.

Some areas to review include:

• Business bank accounts.

• Business credit cards.

• Loans and lines of credit.

• Payroll records.

• Equipment and major purchases.

• Owner contributions and distributions.

• Business expenses.

• Year-end account balances.

Bank and credit card accounts should generally be reconciled to the corresponding statements.

If your QuickBooks or other accounting records contain significant uncategorized transactions, unreconciled accounts, duplicate transactions, or balances that do not make sense, those issues should ideally be addressed before the tax return is prepared.

Good bookkeeping does more than make tax preparation easier. It also gives the business owner a clearer picture of how the company is actually performing.

Review Your Profit and Loss Statement

The profit and loss statement provides a summary of the business's revenue and expenses.

Before filing, review the report and ask whether the numbers appear reasonable.

Does the revenue match what you believe the business earned? Are there unusually large expenses? Are personal expenses mixed into the business accounts? Are there transactions that appear to have been categorized incorrectly?

A relatively simple review can sometimes identify problems that might otherwise flow directly into the tax return.

It can also help identify changes in the business that may be relevant for current-year tax planning.

Don't Ignore the Balance Sheet

Business owners often focus on the profit and loss statement because it shows income and expenses. The balance sheet, however, can be equally important.

The balance sheet includes information about cash, assets, loans, credit cards, liabilities, and owner or shareholder equity.

Unexpected negative balances, old loans that have already been repaid, incorrect cash balances, or unusual shareholder or partner accounts can indicate that additional bookkeeping cleanup may be necessary.

These issues can become more difficult to correct when incorrect balances continue carrying forward from one year to another.

S-Corporation Owners Should Review Payroll and Compensation

Payroll is an important consideration for S-Corporation owners.

Shareholders who perform services for their S-Corporation generally need to consider reasonable compensation and payroll requirements.

Before filing the S-Corp return, review whether shareholder wages were properly processed through payroll and whether the amounts recorded in the accounting system agree with the payroll records.

If there are differences between payroll reports, W-2s, payroll tax filings, and the company's accounting records, those discrepancies should ideally be resolved before filing.

Review Owner Distributions and Contributions

Owners of closely held businesses frequently transfer money between themselves and their companies.

For an S-Corporation, these transactions might represent shareholder distributions, contributions, reimbursements, wages, or loans.

For an LLC taxed as a partnership, payments and distributions to partners may also have different tax treatments depending on the circumstances.

These transactions should be properly identified rather than simply categorized as withdrawals or miscellaneous expenses.

Large distributions, contributions, or unusual owner transactions deserve additional attention before the return is finalized.

Shareholder and Partner Basis Can Matter

Basis can become particularly important when an S-Corporation or partnership has losses, significant distributions, owner contributions, or changes in ownership.

A business loss appearing on a tax return does not necessarily mean the owner can automatically deduct the entire loss on an individual return. Various limitations may apply.

For S-Corporation shareholders, maintaining accurate basis records is especially important when the company has losses or makes substantial distributions.

If your business experienced significant losses or owner transactions during the year, basis may need additional review before the business and individual returns are completed.

Review Major Business Purchases

Did your business purchase a vehicle, computers, equipment, machinery, furniture, or other significant assets during 2025?

Make sure those purchases are properly identified in the accounting records and provided to your tax professional.

Major purchases are not always treated the same way as ordinary operating expenses. Depending on the circumstances, they may need to be depreciated or may qualify for other tax treatment.

Similarly, if the business sold or disposed of equipment or other assets, those transactions should also be reviewed.

Remember That Your Business Return Can Affect Your Individual Return

For S-Corporations and LLCs taxed as partnerships, business income generally flows through to the owners.

The business return produces a Schedule K-1, which is then used when preparing the owner's individual tax return.

This makes accuracy particularly important. An error on the business return can potentially carry over to the owner's individual return.

It is also one reason business owners should avoid waiting until the last few days before the September deadline to begin reviewing their accounting records.

Use Your 2025 Business Return to Start Planning for 2026

Completing an extended business return should not only be about closing out the prior year.

Your 2025 return can provide valuable information about the business and help with planning for the remainder of 2026.

Business owners may want to review current profitability, estimated tax payments, payroll, owner compensation, retirement contributions, major purchases, and distributions.

If your LLC or S-Corporation has grown significantly, added employees, taken on debt, or experienced a major change in profitability, the tax strategy that worked previously may no longer be appropriate.

There is still time before year-end to evaluate the current year and consider whether adjustments should be made.

Getting Ready for the September Deadline

If your LLC or S-Corporation is on extension, now is a good time to make sure your accounting records and tax information are ready.

Reviewing the books before filing can help identify missing transactions, incorrect balances, payroll discrepancies, owner transactions, and other issues that could affect the return.

At Pacific Tax and Investments, we work with LLCs, S-Corporations, and other small businesses on tax preparation, tax planning, accounting, and QuickBooks. Our approach is to look beyond simply preparing the business tax return and help clients understand how their accounting, business activity, and taxes fit together.

If your 2025 LLC or S-Corporation tax return is still on extension, or your accounting records need to be reviewed before filing, we would be happy to help.

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