Year-End Tax Planning Strategies for Small Business

April 17, 2026

The tax moves you make between October and December directly determine what you owe in April. Most small business owners don't start thinking about tax planning until they're sitting across from their CPA in February — by then, the best strategies have expired. Here's what to do before December 31.

Step 1: Run a Year-End Income Projection

Before you make any moves, you need to know where you stand. Pull your profit and loss statement through September or October, then project November and December based on your pipeline, recurring revenue, and typical seasonal patterns.

Key numbers to estimate:

• Projected net business income for the full year
• Total estimated tax liability (federal + state + self-employment)
• Estimated tax payments already made (Q1-Q3, plus any W-2 withholding)
• Gap between what you've paid and what you'll owe

This projection is the foundation for every strategy below. If you're working with a small business CPA, schedule a Q4 planning meeting to review these numbers together.

Step 2: Time Your Income and Expenses

Accelerate Expenses Into This Year

If your income is higher this year than you expect next year, pull deductible expenses into December:

• Prepay January rent — if your lease allows it, pay January's rent in December for an extra month's deduction
• Stock up on supplies — office supplies, inventory, materials you'll use in Q1
• Pay outstanding vendor invoices before December 31 instead of waiting until January
• Renew annual subscriptions — software, insurance, professional memberships
• Make charitable contributions — C-Corps can deduct up to 10% of taxable income; pass-through owners deduct on personal returns

Defer Income to Next Year

For cash-basis businesses (most small businesses), income is taxable when received. If you're trying to reduce this year's tax bill:

• Send December invoices with January payment terms — invoice on December 15 with net-30 means payment arrives in January
• Delay project completion — if a project milestone triggers a payment, consider whether a January completion date makes sense
• Hold off on collections — don't aggressively collect December receivables if deferring that income saves taxes

Important caveat: never defer income if it creates cash flow problems. Tax savings mean nothing if you can't make payroll. And if you use accrual accounting, income is recognized when earned regardless of when payment is received.

Step 3: Maximize Retirement Contributions

Retirement contributions are the most powerful year-end deduction because they reduce your taxable income dollar-for-dollar while building long-term wealth. 2026 contribution limits:

• Solo 401(k) employee deferral: $23,500 ($31,000 if age 50+). Must be contributed by December 31.
• Solo 401(k) employer contribution: Up to 25% of net self-employment income. Can be contributed until your tax filing deadline.
• SEP-IRA: Up to 25% of net self-employment income, maximum $70,000. Can be contributed until your filing deadline (October 15 with extension). This is the most flexible option if you missed the December 31 window.
• SIMPLE IRA: $16,500 employee deferral ($20,000 if 50+) by December 31, plus employer match.

A business owner netting $200,000 could shelter $50,000+ in a Solo 401(k) — saving $12,000-$18,500 in federal income tax alone, depending on their bracket. If you haven't set up a retirement plan yet, a Solo 401(k) must be established by December 31 to make employee contributions for this year (employer contributions can still be made through the filing deadline). A SEP-IRA can be established and funded all the way up to your filing deadline.

Step 4: Make Strategic Equipment Purchases

Section 179 Deduction

Section 179 allows you to deduct the full purchase price of qualifying business equipment in the year it's placed in service, rather than depreciating it over several years. For 2026:

• Maximum deduction: $1,250,000
• Phase-out threshold: Begins at $3,130,000 in total equipment purchases
• Qualifying assets: Computers, office furniture, machinery, vehicles over 6,000 lbs GVWR, off-the-shelf software

If you need a $40,000 work truck (over 6,000 lbs GVWR), buying it and placing it in service before December 31 gives you the full $40,000 deduction this year instead of depreciating it over 5 years.

Bonus Depreciation

Bonus depreciation allows an 80% first-year deduction on qualifying new and used assets placed in service in 2026. This stacks with Section 179 — though most small businesses use one or the other, not both on the same asset. The 80% rate is down from 100% in prior years (it drops 20% annually), so 2026 is more favorable than 2027 will be at 60%.

Critical timing rule: the asset must be placed in service by December 31 — meaning received and operational, not just ordered or paid for. A computer ordered on December 28 that arrives January 3 doesn't qualify for this year's deduction.

Step 5: Review Your Entity Structure

Year-end is the ideal time to evaluate whether your current entity structure is still optimal. If you're operating as a sole proprietor or LLC and your net income exceeds $80,000, an S-Corp election could save you $8,000-$15,000 annually in self-employment tax.

The S-Corp election (Form 2553) for next year must be filed by March 15. Use your year-end planning meeting to model the impact with your CPA and decide before the deadline.

Step 6: Harvest Tax Losses in Your Portfolio

If you have a taxable investment account (not retirement), review positions for tax-loss harvesting opportunities. Selling investments at a loss generates capital losses that offset capital gains, plus up to $3,000 in ordinary income per year. Excess losses carry forward indefinitely.

Be aware of the wash sale rule: you cannot repurchase a substantially identical security within 30 days before or after the sale, or the loss is disallowed. Replace the sold position with a similar (but not identical) fund to maintain your allocation.

Step 7: Adjust Your Q4 Estimated Payment

If your year-end strategies meaningfully reduce your projected tax liability, you can lower your Q4 estimated payment (due January 15). Use the annualized income installment method (Form 2210, Schedule AI) to support the lower payment and avoid underpayment penalties.

Conversely, if your income was higher than expected, increase your Q4 payment to avoid a surprise balance and penalty at filing time. The IRS underpayment penalty runs roughly 8% annualized in 2026 — it's cheaper to pay now.

Step 8: Get Your Books in Order

Year-end tax planning only works if your financial data is accurate. Before your planning meeting:

1. Reconcile all bank and credit card accounts through the current month
2. Categorize all transactions — uncategorized expenses are invisible deductions
3. Separate personal from business expenses if you've been commingling
4. Gather receipts for any deductions over $75 (IRS receipt requirement)
5. Review accounts receivable — write off any uncollectible invoices as bad debt (accrual basis only)

Year-End Tax Planning Checklist

• Run income projection through year-end
• Prepay deductible expenses where it makes sense
• Defer December income to January (cash-basis businesses)
• Maximize retirement plan contributions before applicable deadlines
• Purchase and place in service any needed equipment before December 31
• Evaluate S-Corp election for next year
• Harvest tax losses in taxable investment accounts
• Adjust Q4 estimated payment based on updated projections
• Reconcile books and gather documentation
• Schedule a year-end planning meeting with your small business CPA

The difference between reactive tax preparation and proactive tax planning is typically $5,000-$20,000 per year for a small business. Every strategy on this list has a deadline — most of them December 31. Start now.