7 Year-End Money Moves to Make Before December 31st
Only days left in 2025. Here are the tax-saving, wealth-building moves you need to make before the year resets—with calculators to run your numbers.
The clock is ticking. Once January 1st hits, your 2025 tax optimization window slams shut.
Most people think about their finances in January. Smart people act in December. Here are the money moves that could save you thousands—if you make them before the ball drops.
1. Max Out Your 401(k)
2026 Limit: $23,000 ($30,500 if you're 50+)
If you haven't maxed out your 401(k), check your last few paychecks. You may be able to increase your contribution percentage for December to squeeze in more.
The Math
| Tax Bracket | Contribution | Immediate Tax Savings |
|---|---|---|
| 22% | $23,000 | $5,060 |
| 24% | $23,000 | $5,520 |
| 32% | $23,000 | $7,360 |
| 35% | $23,000 | $8,050 |
That's money back in your pocket—plus decades of tax-deferred growth.
***** Check your last paycheck stub for YTD 401(k) contributions. Subtract from $23,000 to find your remaining room. Contact HR or adjust in your benefits portal ASAP.
2. Use Your FSA Balance (Use It or Lose It)
Flexible Spending Account funds typically expire December 31st. Some plans offer a grace period or $610 carryover, but many don't.
Quick ways to use FSA funds:
- Stock up on contact lenses, glasses
- Schedule a dental cleaning
- Buy first aid supplies, sunscreen, bandages
- Get prescription refills
- Purchase eligible OTC medications
Don't let free money evaporate.
3. Tax-Loss Harvest Your Portfolio
If you have investments that are down this year, you can sell them to:
- Offset capital gains - Save 15-20% on profitable sales
- Deduct up to $3,000 against ordinary income
- Carry forward excess losses to future years
Example
| Scenario | Tax Savings |
|---|---|
| $5,000 loss offsets $5,000 gain (24% bracket) | $1,200 saved |
| $3,000 loss deducted from income (24% bracket) | $720 saved |
Important: Avoid the wash sale rule. Don't buy back the same or "substantially identical" security within 30 days. Buy a similar (but different) fund instead.
4. Make Charitable Donations
Donations made by December 31st count for your 2025 taxes.
Strategies:
- Donate appreciated stock - Avoid capital gains AND get the deduction
- Donor-advised fund - Front-load multiple years of giving for a larger deduction this year
- Bunch donations - If you're close to the standard deduction threshold, combining donations can push you over
| Filing Status | 2025 Standard Deduction |
|---|---|
| Single | $14,600 |
| Married Filing Jointly | $29,200 |
If your itemized deductions are close to these numbers, strategic charitable giving could tip the scales.
5. Max Out Your HSA
2026 Limits: $4,150 (individual) / $8,300 (family)
HSAs are the only triple-tax-advantaged account:
- Tax deduction on contributions
- Tax-free growth
- Tax-free withdrawals for medical expenses
You have until April 15, 2025 to contribute for 2025—but why wait? Get those funds invested and growing.
Calculate your take-home pay with HSA contributions →
6. Review Your Asset Allocation
Year-end is the perfect time to rebalance:
- Did stocks outperform? You may be overweight equities
- Are you on track for retirement? Run a projection
- Does your risk level still match your timeline?
Market movements throughout the year can drift your allocation. A 70/30 portfolio might now be 80/20.
7. Set Up Automatic Increases for 2025
While you're thinking about it, set up automatic contribution increases:
- 401(k): Increase by 1-2% on January 1st
- IRA: Set up automatic monthly transfers
- Brokerage: Schedule recurring investments
The 2025 401(k) limit is $23,500 ($31,000 if 50+). Plan to hit it.
The Year-End Checklist
| Action | Deadline | Potential Savings |
|---|---|---|
| Max 401(k) | Dec 31 | $5,000-8,000+ |
| Use FSA | Dec 31 (or grace period) | $100-2,000+ |
| Tax-loss harvest | Dec 31 | $500-5,000+ |
| Charitable donations | Dec 31 | Varies |
| HSA contribution | April 15, 2025 | $1,000-2,500+ |
| Rebalance portfolio | Anytime | Risk management |
Run Your Numbers
Don't guess—calculate:
- US Salary Calculator - See how 401(k) changes affect take-home pay
- FIRE Calculator - Are you on track for retirement?
- Investment Returns Calculator - Project your portfolio growth
- Debt Payoff Calculator - Plan your 2025 debt attack
The Bottom Line
December is when wealth is built—or lost to procrastination. Every move on this list takes less than 30 minutes. The tax savings can be thousands.
You have days left. Make them count.