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Your Year-End Business Checklist: TKA Style

The fourth quarter always sneaks up fast, but it’s the most important time of year to get your books, taxes, and strategy in order. At The King’s Accountant (TKA), we like to keep it simple with our T-K-A approach: Time-Sensitive Tasks, Keep Organized, and Advance Planning.

Whether you’re a brand-new entrepreneur or a seasoned business owner, this checklist will help you close out 2025 with confidence and hit the ground running in 2026.

T – Time-Sensitive Tasks

Deadlines drive everything at year-end, and missing one can mean penalties, stress, or missed opportunities. Here are the key dates to circle:

  • Oct 15 – Extended corporate and personal tax returns are due (1120 & 1040).
  • Dec 31 – The big cutoff: run payroll and bonuses, make deductible purchases, finalize charitable contributions, and complete retirement contributions or rollovers.
  • Jan 15, 2026 – Final 2025 estimated tax payment is due.
  • Jan 31, 2026 (Feb 1) – W2s & 1099s are due.  
  • Mar 16, 2026 – S-Corp and Partnership returns (and payments) are due unless you file an extension.
  • Apr 15, 2026  – C-Corp and personal returns (and payments) are due unless you file an extension.

Other timelines to keep in mind: 

  • Oct 15 – Nov 15 – Meet with your tax professional to review your 2025 results. This is your window to make adjustments before December 31.
  • Nov 15 – Dec 15 – Review employee and contractor information. Verify addresses, gather W-9s, and prep for year-end filings.


Pro Tip for advanced readers: Custodians like Edward Jones and Fidelity often require new retirement plans (SEP, SIMPLE, 401k) to be set up as early as October, even though contributions can be made later. Don’t wait until December 31 to start that conversation.

K – Keep Organized

A smooth tax season starts with clean records. If your books are a mess, your accountant will spend more time untangling data than planning strategy. Here’s where to focus:

  • Reconcile your bank and credit card accounts.
  • Double-check your mileage tracker.
  • Gather receipts for home office use, utilities, and other deductions.
  • Verify employee addresses and emails for W-2 delivery.
  • Collect W-9s from contractors now, not in January.
  • Review your year-to-date financials for errors or misclassifications.

Pro Tip for advanced readers: Flag repairs and equipment purchases over $2,500, as they may qualify for the de minimis safe harbor election or require capitalization and depreciation. Planning now avoids surprises later (including projected purchases before December 31st).

A – Action Planning

Once the urgent deadlines are handled and your records are in shape, you can step back and look at the bigger picture. Year-end is the perfect time to make intentional moves:

  • Reconcile your bank and credit card accounts.
  • Double-check your mileage tracker.
  • Gather receipts for home office use, utilities, and other deductions.
  • Verify employee addresses and emails for W-2 delivery.
  • Collect W-9s from contractors now, not in January.
  • Review your year-to-date financials for errors or misclassifications.

Pro Tip for advanced readers: Look at A/R and A/P timing as a tax planning tool to hedge against both GROWTH or INFLATION. Strategically collect (or DELAY COLLECTING) overdue client invoices and pay (or DELAY PAYING) vendor payments.

Wrapping Up

Q4 can feel overwhelming, but breaking it down into Time-Sensitive Tasks, Keeping Organized, and Advance Planning (T-K-A) helps you prioritize what matters most. 

For those just starting out, focus on the basics: hit your deadlines, keep your records clean, and don’t miss deductions. For the advanced crowd, fine-tuning compensation, depreciation, and entity structure can unlock real tax savings.

Either way, the key is the same: don’t wait until January! Take action now, and you (and your tax accountant) will thank yourself when tax season rolls around.