December is when refunds are made or lost
After January 1, the year is locked. Every meaningful tax-saving move has to happen by December 31. Here's the checklist we walk every client through during Q4.
For individuals and families
Retirement contributions
- Max your 401(k) up to the annual limit
- Top off your IRA (you actually have until April 15, but earlier is better)
- HSA contributions if you're on a qualifying high-deductible plan — triple tax advantage
Charitable giving
- Donor-advised funds let you bunch multiple years of giving into one
- Appreciated stock beats cash for both you and the charity
- Get receipts dated December 31 or earlier; for $250+ gifts, written acknowledgment is required
Realize losses (or gains) on purpose
- Tax-loss harvesting in taxable brokerage accounts can offset gains
- Watch for wash sale rules (30-day window)
- For low-income years, consider realizing gains in the 0% capital-gains bracket
Medical expenses
- If you're close to the 7.5% AGI threshold, accelerating elective procedures into this year may unlock a deduction
For business owners
Equipment and software
- Section 179 lets you expense qualifying purchases up to the annual limit
- Bonus depreciation rules continue to phase down — confirm current-year percentages
- "Placed in service" by December 31 matters more than "ordered" by December 31
Owner compensation (S-Corps)
- Run final payroll for the year before December 31
- Make sure your reasonable salary is on the books, not just promised
- True up health insurance reporting on the W-2 if applicable
Retirement plans for the business
- SEP-IRAs can be funded up to the tax filing deadline
- Solo 401(k)s usually need to be established by December 31, even if funded later
- Defined benefit plans for high earners — separate timelines, big deductions
Receivables and payables timing
- Cash-basis businesses can defer December invoices into January or accelerate January expenses into December
- Accrual-basis businesses have less flexibility but still have moves
For everyone
"The clients who never have an April surprise are the ones who looked at their numbers in November."
- Run a draft return with what you know now
- Compare withholding + estimated payments against projected liability
- Make a final estimated payment by January 15 to avoid underpayment penalties
- Confirm life events are reflected: marriage, divorce, new dependent, home purchase, business launch
Want a real one?
This is the public version. Our actual checklist is customized for each client and runs about three pages. If you'd like one tailored to your situation, book a year-end planning session — most clients save more than the cost of the session in the first year alone.
