Quick Answer: For most strategies, yes. The window that matters runs from now through December 31, 2026, because many deductions, purchases, and retirement decisions must happen within the tax year. Starting in October gives you time to project your income, choose the right moves, and avoid year-end scrambling.
Many business owners think of tax planning as something that happens in March or April. By then, most options have expired. Tax season is when you report what happened. Q4 is when you can still change it.
Why does Q4 matter more than tax season?
Once December 31 passes, the year is closed. You cannot go back and buy equipment, fund a 401(k) deferral, or shift income into a different year. That is why the first step is a projection of your 2026 taxable income. It tells you whether you are on track for a bigger bill than expected and how much room you have to act.
Should you buy equipment before December 31?
Federal law now allows 100 percent bonus depreciation on qualifying property acquired and placed in service after January 19, 2025. The Section 179 expensing limit for 2026 is roughly $2.56 million. For Central Valley businesses, that can apply to trucks, tractors, shop equipment, and technology.
Two cautions. First, the equipment must be placed in service, ready for use, by December 31. Ordering it is not enough. Second, California does not follow federal bonus depreciation, and its Section 179 limit is much lower, so your state result will differ. Never buy something you do not need just to create a deduction.
What retirement contributions can you still make?
Employee 401(k) deferrals generally need to be completed by December 31. The 2026 limit for most workers is $24,500, with higher limits for those age 50 and older. Some plans, such as a SEP IRA, can be funded up to the due date of your return, including extensions. Retirement contributions are one of the few tax moves that also build your future, so they deserve a look.
How do the new charitable giving rules affect year-end gifts?
Starting in 2026, taxpayers who do not itemize may be able to deduct up to $1,000 of cash gifts to qualifying charities, or $2,000 for joint filers. Taxpayers who do itemize now face a floor tied to a share of income. That makes the timing and size of your giving more important. Some donors bunch several years of gifts into one, often using a donor-advised fund.
Ask your tax preparer to confirm you are eligible, since the deduction has specific rules for qualifying organizations and documentation.
How can you time income and expenses?
If you are on the cash method, you may be able to delay year-end invoices, pay deductible expenses before December 31, or collect receivables in the year that fits your projection. Do this carefully. Pushing income into 2027 only helps if 2027 will not be a higher-income year.
Also review your year-to-date receivables and unpaid bills. Small timing choices, made deliberately, can smooth your tax bill across years.
How do estimated taxes fit into your Q4 plan?
Underpaying estimated taxes can trigger penalties even if you pay the full balance at filing. Safe harbor rules generally protect you if your payments meet certain percentages of your current or prior year tax, and those percentages vary based on income. A Q4 projection shows whether you are on track or need a larger fourth-quarter payment. Do this before the January 15 due date, not after.
Is your business structure still the right fit?
The 20 percent qualified business income deduction is now permanent, which makes entity structure and owner pay worth reviewing. California also offers an elective pass-through entity tax through 2030 that can help owners work around the federal SALT cap. Ask whether that election makes sense for your business.
Want to know what your 2026 return could look like? Contact DDC CPA today. Let us build your year-end plan while there is still time.
Frequently Asked Questions
What is the deadline for year-end tax moves in 2026?
For most strategies, December 31, 2026. Some, like SEP IRA contributions, can extend to your filing deadline, but do not assume. Confirm the deadline for each move.
Do I have to pay for equipment before December 31 to deduct it?
You generally need to buy the equipment and place it in service by December 31. Financed purchases can still qualify. Talk with your CPA before signing anything.
When is the fourth-quarter estimated tax payment due?
For individuals, the fourth-quarter 2026 estimated payment is due January 15, 2027. C corporations make their final installment on December 15.
I filed an extension for 2025. Is it too late for 2026 planning?
No. Your 2025 extension only affects the prior-year return. Planning for 2026 is a separate task, and the best window to act is now.
What is the biggest Q4 tax mistake business owners make?
Waiting until January. By then, the year is closed, and the moves that would have reduced your bill, such as purchases and contributions, are no longer available.