Year-End Tax Planning for Contractor Businesses

Equipment must be placed in service — available and ready for business use, not just ordered — before December 31 to qualify for Section 179 or 2026’s 100% bonus depreciation rate, which OBBBA made permanent. The difference between paying $45,000 in taxes and paying $30,000 in taxes is almost entirely determined by decisions made between September and December 31; after the year closes, you can calculate liability but not reduce it.

Here is the contractor-specific year-end planning sequence.

What Should You Do in September to Project and Review Your Taxes?

Build the year-end income projection

Pull your current year-to-date books. Project Q4 revenue based on signed contracts, backlog, and seasonal pattern. Project Q4 expenses. Arrive at an estimated full-year net income.

This number drives every decision below. Without it, you’re making planning decisions blind.

Review your S-corp salary

If your revenue has grown significantly from when you originally set your salary, the current salary may be unreasonably low — creating IRS audit risk. More practically: a higher salary may support a larger retirement contribution.

Review the salary against:

• Current-year net income trajectory
• Your role in the business (active trade work vs. management)
• BLS wage data for your trade and market
• The contribution ceiling you need to hit your retirement target

Salary changes must be reflected in payroll before December 31. If you need to increase your salary, give your payroll provider time to process changes and run any catch-up payroll by late December.

Check your entity structure

If you’ve been operating as a sole prop or disregarded entity and your net income has crossed $90,000 this year, September is the time to model whether an S-corp election would be net positive. If yes, you likely can’t get it effective for this year (the March 15 deadline is past), but you can file Form 2553 now and have it take effect January 1 of next year. That gets you the full benefit starting next year instead of waiting another filing cycle.

What Retirement Planning Should You Handle in October?

Establish or review your retirement plan

If you don’t have a Solo 401(k) and want one for this tax year, October is the window to set it up. Most brokerage accounts (Fidelity, Schwab, Vanguard) can be opened in 1–2 weeks if you have the EIN. Establishment must happen by December 31.

Calculate your optimal contribution

This calculation requires your projected full-year net income, your salary (if S-corp), and your target retirement balance. The CPA produces:

• Maximum allowable contribution (employee deferral + employer)
• The portion that can wait until the return due date (employer profit-sharing)
• The portion that must be elected by December 31 (employee deferral)
• The cash flow impact

Cash balance plan decisions

If you’re 45+ with consistent income above $250,000, October is when the actuary calculates your required cash balance contribution. These plans require funding commitments — if you’re in one, get the required contribution amount confirmed and budget for it.

What Equipment and Expense Timing Decisions Should You Make in November?

Equipment purchases

Section 179 expensing and bonus depreciation (100% in 2026) require that the asset be placed in service before December 31. Placed in service means available and ready for business use — not just ordered.

November is the window to buy, receive, and deploy business equipment that you’ve been putting off. Work trucks, trailers, power tools, diagnostic equipment, generators — anything that qualifies as depreciable business property.

Bonus depreciation is 100% in 2026: OBBBA made 100% bonus depreciation permanent for qualifying property placed in service after January 19, 2025, reversing the phase-down that had been scheduled to reach 20% by 2026. Combined with Section 179, most contractor equipment purchases are now fully deductible in Year 1 — but placed-in-service timing before December 31 still controls which tax year gets the deduction.

Prepaid expenses

Cash-basis contractors can accelerate deductions by prepaying expenses for services to be received in the following year:

• Annual business insurance renewals — pay in December
• Software subscriptions — pay December for the following year
• Trade association dues renewing in January

What Are the Hard December Deadlines for Contractor Tax Planning?

The payroll timing trap: Many payroll providers close their December 31 payroll by December 26 or 27. If your salary needs adjustment, the payroll provider needs the instruction before that cutoff. Miss it and you’re locked out of the adjustment for the year.

What Tax Planning Opportunities Survive December 31?

A few items don’t expire at year-end:

• Solo 401(k) employer profit-sharing contribution: Can be funded up to the tax return due date including extensions (October 15 of the following year)
• SEP-IRA: Both establishment and contribution can be made as late as October 15
• Health insurance premiums: Deducted on the return for premiums paid during the year — no separate December deadline

What Is the Contractor Tax Planning Gap?

The most common contractor tax mistake: getting the return prepared in March, seeing a large tax bill, and then realizing there were planning opportunities that expired in December. By March, the only option is to minimize future taxes — not last year’s.

Contractors who work with CPAs who initiate contact in Q3 and Q4 capture significantly more of the available planning value than those who call in January.

Contractor retirement accounts — contribution math by income level and plan type.

Contractor tax deductions — the complete checklist with year-end deadlines.

This article is educational. Reflects 2024 tax law. Consult a licensed CPA for advice specific to your situation.