Data Notice: Tax figures and deadlines cited in this article reflect projected 2026 rules. Deadlines are firm — most year-end tax moves must be completed by December 31. Confirm current rules at IRS.gov.

Year-End Tax Moves: 15-Point December Checklist

December 31 is the hard deadline for most tax-saving strategies. Once the calendar turns, these opportunities disappear for the tax year — permanently. This checklist covers 15 actionable moves organized by urgency and impact. Each one includes the deadline, the dollar impact, and who benefits most. Start with the highest-impact items and work down.

High Impact: Do These First

1. Max Out Your 401(k) Contributions

Deadline: December 31 (last payroll of the year) Impact: Up to ~~$23,500 in tax-deductible contributions (~~$31,000 if 50+, ~$34,750 if 60-63)

Check your YTD contributions on your most recent pay stub. If you are behind, increase your contribution percentage for the remaining paychecks. Some employers allow a one-time lump-sum contribution — ask HR.

See Tax-Advantaged Accounts Ranked for the full hierarchy.

2. Tax-Loss Harvest Your Portfolio

Deadline: December 31 (trades must settle by year-end; allow T+1 settlement time) Impact: Unlimited offset against capital gains + $3,000 against ordinary income

Review your taxable brokerage account for positions trading below your cost basis. Sell to realize the loss, then reinvest in a similar (not substantially identical) fund to maintain market exposure. The wash sale rule prohibits buying the same security within 30 days.

See Tax-Loss Harvesting Guide for the complete process.

3. Harvest Capital Gains at 0% (If in Low Bracket)

Deadline: December 31 Impact: Reset cost basis on appreciated assets at 0% federal tax

If your taxable income is below approximately $48,350 (single) / ~$96,700 (MFJ), sell appreciated investments to realize gains tax-free. Immediately repurchase to reset your basis at the higher price. There is no wash sale rule on gains — only losses.

See Capital Gains Tax Rates 2026 for the exact thresholds.

4. Execute Roth Conversions

Deadline: December 31 Impact: Convert Traditional IRA to Roth at controlled tax rates

If you are in a low-income year (early retirement, sabbatical, business down year), convert Traditional IRA assets to Roth up to the top of your target tax bracket. Pay income tax now at a low rate; the funds grow and are withdrawn tax-free in retirement.

See Roth Conversion Ladder Strategy for the math.

5. Make Charitable Contributions (Cash or Stock)

Deadline: December 31 (checks must be mailed; credit card charges processed) Impact: Deduction up to 60% of AGI for cash, 30% for appreciated property

If you itemize: donate appreciated securities directly to avoid capital gains tax. If you do not typically itemize: bunch multiple years of gifts into a donor-advised fund to exceed the standard deduction. See Charitable Giving Strategies.

6. Qualified Charitable Distributions (Age 70½+)

Deadline: December 31 Impact: Up to approximately $105,000 excluded from AGI

Transfer IRA funds directly to a charity. Counts toward your RMD, reduces your AGI, and can lower Social Security taxation and Medicare IRMAA surcharges.

Medium Impact: Don’t Overlook

7. Take Your Required Minimum Distribution

Deadline: December 31 (April 1 of the year following the year you turn 73, for first RMD only) Impact: Avoids the 25% penalty on the missed amount

If you turned 73 in a prior year, your RMD deadline is December 31. Missing it triggers a 25% excise tax (reduced from 50%) on the amount not distributed. Check with your IRA custodian to confirm the amount.

8. Contribute to a 529 Plan

Deadline: December 31 (for state tax deduction in the current year) Impact: State tax deduction in 34+ states

Contributions do not reduce federal taxes, but 34 states offer a deduction or credit. Check your state’s limit. You can superfund up to approximately $95,000 ($190,000 MFJ) using the 5-year gift tax averaging election.

See 529 College Savings Plans.

9. Bunch Medical Expenses

Deadline: December 31 Impact: Deductible to the extent they exceed 7.5% of AGI

If your unreimbursed medical expenses are near the 7.5% threshold, schedule and pay for planned procedures, dental work, glasses, or hearing aids before year-end. The deduction is available only if you itemize.

10. Prepay State and Local Taxes (SALT)

Deadline: December 31 Impact: Up to $10,000 SALT deduction

If you are itemizing and have room under the $10,000 SALT cap, pay your January state estimated tax payment in December. This is useful if your total itemized deductions are on the margin. Note: the $10,000 cap limits the benefit for high-tax-state residents.

11. Max Out Your HSA

Deadline: April 15 of the following year (but payroll deductions must stop December 31) Impact: ~$4,300 individual / ~$8,550 family deduction

Unlike 401(k) contributions, HSA contributions can be made up to the tax filing deadline. But payroll deductions stop at year-end. If you are short, make a direct deposit to your HSA before April 15.

See HSA Triple Tax Advantage.

12. Defer or Accelerate Income

Deadline: December 31 Impact: Varies — can shift thousands between tax years

Defer income if you expect to be in a lower bracket next year (retirement, sabbatical, job change): delay invoicing clients, postpone year-end bonuses if your employer allows, hold off selling investments.

Accelerate income if you expect to be in a higher bracket next year (promotion, business growth, Roth conversion in current year): invoice early, request bonus payment before year-end, realize capital gains now.

Lower Impact but Still Valuable

13. Review Withholding to Avoid Penalties

Deadline: December 31 (for W-4 adjustments on final paycheck) Impact: Avoids underpayment penalties

If you owe significantly more than your withholding covers, increase your W-4 withholding for the last paycheck. W-2 withholding is treated as paid evenly throughout the year, which can retroactively cure underpayment penalties — unlike estimated tax payments, which are applied to the quarter they are paid.

14. Use Your FSA Balance

Deadline: December 31 (or March 15 grace period if your employer offers one) Impact: Recover use-it-or-lose-it FSA funds

Unlike HSAs, Flexible Spending Accounts expire. Some plans offer a $640 carryover or 2.5-month grace period. Check your plan terms and spend remaining balances on eligible expenses.

15. Fund Coverdell Education Savings Account

Deadline: December 31 Impact: Up to $2,000 per beneficiary per year, tax-free growth

Less common than 529 plans but offers broader investment options and can be used for K-12 expenses. Income limits apply: phase-out starts at $95,000 (single) / $190,000 (MFJ).

Year-End Tax Calendar

Date	Action
Early December	Review YTD 401(k) contributions; adjust final paychecks
Mid-December	Execute tax-loss harvesting trades (allow settlement time)
December 28-30	Last reliable trade settlement dates for December 31
December 31	401(k), Roth conversion, charitable, RMD, 529, FSA deadlines
January 15	Q4 estimated tax payment due
April 15	IRA, HSA contribution deadlines for prior tax year

Key Takeaways

December 31 is a hard deadline for 401(k) contributions, Roth conversions, tax-loss harvesting, charitable gifts, RMDs, and 529 contributions
Tax-loss harvesting and 0% capital gains harvesting require trades to settle by year-end — execute by December 28-29
QCDs (age 70½+) reduce AGI and can lower Social Security tax and Medicare premiums
Bunching charitable gifts into a donor-advised fund lets non-itemizers capture the deduction
HSA and IRA contributions have until April 15, but all other major moves expire December 31

Next Steps

Review Tax Planning Strategies for the full annual playbook
Use the Tax Bracket Calculator to model your December moves
See Charitable Giving Strategies for DAF and QCD execution
Hire a Tax Professional for personalized year-end planning

This content is for educational purposes only and does not constitute financial or tax advice. Consult a licensed tax professional for your specific situation.

Sources

IRS — Tax Inflation Adjustments for 2026 — accessed April 2026
IRS — Retirement Topics: Required Minimum Distributions — accessed April 2026
IRS — Charitable Contributions — accessed April 2026
IRS — Tax Withholding Estimator — accessed April 2026
SSA.gov — Retirement Benefits — accessed April 2026