Year-End Tax Planning Checklist: An Excel-Powered Guide

Year-End Tax Planning Checklist: An Excel-Powered Guide

Year-end is your last window to make moves that legally lower tax. The right tactics depend on method of accounting, entity type, and industry. Use these six windows to turn year-end work into year-round advantage.

Review and reconcile financials

Accurate books drive accurate tax.

• • Reconcile bank, credit card, and vendor balances.
  • Verify income/expense classifications and fix misposts.
  • Confirm accounting method and cut-off. Cash vs. accrual timing differs.
    Best time: January–February

Maximize deductions before 12/31

Timing matters.

• • Prepay eligible costs (rent, insurance, certain services) only if the 12-month rule is met.
  • Place eligible equipment/software in service by 12/31 to claim §179 or bonus. For tax years beginning in 2025, §179 expensing is up to $2,500,000, phasing out starting at $4,000,000 of §179 property placed in service.
  • For bonus depreciation under §168(k), the placed-in-service year controls. Elections are made on Form 4562 by class of property.
    Best time: March–May

Capture credits and incentives

Most credits require contemporaneous documentation.

• • Research credit (Form 6765): define qualifying activities and track support.
  • Clean-energy credits: confirm eligibility, placed-in-service timing, and any enhanced amounts under current guidance.
    Best time: May–August

Depreciation and capex modeling

Model §179 vs. bonus vs. MACRS before you buy.

• • Run scenarios on large purchases and listed-property limits.
  • Manage “placed-in-service” dates to maximize first-year deductions.
  • Remember auto caps and how bonus interacts with first-year limits.
    Best time: August–September

Forecast year-end tax liability

Use updated P&L through Q3.

• • Adjust Q4 estimates to hit safe harbors and avoid underpayment penalties. For individuals: pay ≥90% of current-year tax, or 100% of prior-year tax (110% if prior-year AGI > $150,000).
  • Consider deferring income or accelerating deductions within your accounting-method constraints.
  • NOLs generated post-2020 generally carry forward indefinitely, limited to 80% of taxable income. Carrybacks are limited and apply only in specific cases.
    Best time: October

Final 30–45 days: align and execute

Lock in the plan.

• • Finalize compensation/bonuses and charitable gifts by 12/31 per deduction rules.
  • Confirm contract dates, shipment/acceptance, and vendor payments to support timing.
  • Coordinate finance, HR, and ops on payroll cut-offs and year-end reporting.
    Best time: November–December

Why this matters in 2025

With new rules under the One Big Beautiful Bill Act and the 2026 TCJA sunset still looming, timing matters more. Placed-in-service dates, safe-harbor payments, and documentation standards have outsized impact. Businesses that treat tax planning as a year-round process, not a December scramble, save more and avoid costly mistakes.

Excel Tax Group can help you:

• • Identify the right tax windows for your situation.
  • Maximize deductions and credits before deadlines.
  • Align tax strategy with your operational and financial goals.

Schedule your Year-End Planning Consultation and turn your tax checklist into a strategic advantage for 2026.