For most small business owners, year-end tax planning is something that happens in November or December, and ends up being a scramble to get organized before the calendar flips. By that point, some of the most useful options are no longer available, and the decisions that remain are made under pressure rather than with a clear picture of the full year.
Starting that process in September changes what is possible.
At this point in the year, you have a reasonably accurate picture of where your income will land. You know which months were strong and which were slower. You have enough data to make informed decisions about the rest of the year, and enough time to actually implement them.
What Is Worth Reviewing Now
A few areas tend to have the most meaningful impact when reviewed before Q4.
Estimated tax payments. The Q3 payment is due September 15, which is also a natural moment to confirm that your payments for the year are on track. If income has shifted significantly since you last reviewed your estimates, an adjustment now can help you avoid an underpayment penalty or free up cash that is sitting unnecessarily with the IRS.
Equipment and asset purchases. With 100% bonus depreciation restored for 2026 and the Section 179 expensing limit at $2.5 million, businesses planning significant equipment or asset purchases have a strong incentive to time those decisions carefully before December 31. If a purchase is already under consideration, understanding how it affects your 2026 tax position is a useful part of that decision.
Retirement contributions. September is a good time to review whether you are on track to maximize contributions to a SEP IRA, Solo 401(k) or SIMPLE IRA for the year. For 2026, contribution limits are meaningful, up to $70,000 for a SEP IRA or Solo 401(k) depending on your situation. Contributions to these plans reduce taxable income, and for some business owners they represent one of the more significant planning opportunities available before year-end.
Income and expense timing. Cash-basis businesses have some flexibility in how they time income and expenses across year-end. Accelerating a deductible expense into 2026 or deferring income into 2027 can make a real difference in tax liability for the year, but these decisions work best when they are made with a full picture of where things stand, not in the final weeks of December.
The Value of Getting Ahead of This
Year-end tax planning is most effective when it is not rushed. The business owners who tend to be most satisfied with their tax outcomes are the ones who have a conversation with their advisor in September or October, identify the moves that make sense for their situation and implement them deliberately rather than reactively.
At Dunn CPA Firm, this kind of proactive planning is a regular part of how we work with clients. If you want to take a closer look at where your 2026 tax position stands and what options are still available to you, now is a good time to start that conversation.
