The September Tax Checkpoint: Why Q3 Is When Year-End Planning Should Really Begin

September may not get the attention that April does on the tax calendar, but for business owners and many individual taxpayers, it can be one of the most valuable months of the year.

By September, you have enough financial information to see how the year is actually unfolding. Revenue trends are becoming clearer, expenses have had time to develop, investments and business decisions have been made, and your tax picture may look very different than it did at the beginning of the year.

At the same time, there are still several months left to make thoughtful adjustments.

That combination makes September an ideal time to move from simply tracking your finances to actively planning around them.

Start With Your September 15 Obligations

September 15 is an important date for many taxpayers.

For individuals who make estimated tax payments, the third installment for 2026 is due September 15. The date is also the extended filing deadline for many calendar-year S corporations and partnerships.

While meeting the deadline is important, it shouldn’t be the only objective.

For taxpayers making estimated payments, September presents an opportunity to ask whether the amount you planned earlier in the year still reflects your actual financial situation.

Don’t Automatically Assume Last Quarter’s Number Is Still Right

Estimated tax payments can sometimes feel like another recurring bill. Once a payment amount has been established, it’s tempting to continue using it without revisiting the underlying numbers.

But businesses and personal finances rarely move in a straight line.

Perhaps your business had a stronger summer than expected. Maybe expenses increased, you sold an investment, received additional income, purchased equipment, or experienced another significant financial change.

Those developments can affect your tax picture.

September is an excellent time to compare your projections with your actual year-to-date results and determine whether your planning still makes sense.

Look Beyond Revenue

Business owners naturally pay close attention to sales, but revenue tells only part of the story.

A company can increase revenue while simultaneously experiencing pressure on profitability because payroll, materials, insurance, technology, financing costs, or other expenses have increased.

By Q3, you should have enough information to begin asking deeper questions.

Is profitability moving in the same direction as revenue?

Are certain expenses growing faster than expected?

Is cash flow supporting the needs of the business?

Are your margins changing?

Are you carrying costs that no longer make sense?

Accurate financial statements and bookkeeping become especially valuable here. They give you the information needed to identify trends while there’s still time to respond.

Think About Major Purchases Before December

Year-end purchasing decisions are another area where earlier planning can help.

Business owners sometimes reach December and begin looking for expenses or equipment purchases that might reduce taxable income. Tax considerations can certainly be part of the conversation, but they shouldn’t be the only reason to spend money.

A deduction doesn’t make an unnecessary purchase a good business decision.

Instead, begin evaluating potential purchases now. Consider what the business actually needs, when an investment would provide the greatest operational benefit, how it affects cash flow, and what tax treatment may apply.

That creates an opportunity to make a sound business decision that also considers the tax implications.

Review Retirement and Compensation Planning

September is also a useful time to revisit retirement contributions, owner compensation, and other planning considerations.

These decisions can have implications for both the business and the individual owner, which is why they should be considered as part of the broader financial picture rather than in isolation.

Starting the conversation now provides time to evaluate options thoughtfully instead of trying to make several significant decisions during the final weeks of December.

Pay Attention to Changes Within the Business

Some of the most important tax and accounting conversations begin with something that may not initially seem like a tax question.

Did you add employees?

Enter a new state?

Change how owners are compensated?

Purchase significant assets?

Add a new line of business?

Experience a major increase or decrease in revenue?

Begin considering a sale, acquisition, or succession plan?

Changes within a business can create accounting, tax, payroll, or reporting considerations. Bringing your CPA into the conversation early can help identify those implications before decisions are finalized.

Give Yourself Time to Fix the Fundamentals

September is also a good point to address financial housekeeping that has been pushed aside during a busy year.

Maybe your bookkeeping needs attention. Perhaps your accounting software no longer fits the business. Your financial statements may not be giving you the visibility you need, or you may simply have questions about numbers that don’t look quite right.

These issues are much easier to address in September than during the final days of the year.

Clean, accurate financial information creates the foundation for better planning.

Good Tax Planning Isn’t a December Scramble

There’s a common misconception that tax planning means finding last-minute deductions before December 31.

Good planning is much broader than that.

It means understanding where you stand, identifying what has changed, considering what’s ahead, and making informed decisions while you still have options.

September offers an ideal window to do exactly that.

At Waters Hardy, we work with individuals and businesses throughout the year to help them understand their financial picture, stay current with changing tax requirements, and make thoughtful decisions before deadlines create unnecessary pressure.

If you haven’t reviewed your tax and financial strategy recently, don’t wait for December. Contact Waters Hardy to schedule a Q3 planning conversation and make sure you’re prepared for the months ahead.