The December 31 Capital Gains Checklist
- Tally all realized capital gains for 2025: short-term and long-term separately from brokerage statements
- Identify all unrealized losses in taxable accounts: these are candidates for tax-loss harvesting
- Calculate available loss harvesting: Can any losses offset the realized gains?
- Check the 0% bracket capacity: Is your income low enough for any remaining gain to be tax-free?
- Review wash sale exposure: Any prior harvested losses that might be disallowed by recent purchases?
- Plan mutual fund purchases: Avoid buying before ex-dividend dates on high-distribution funds in Q4
- Review IRA vs taxable account holdings: Any assets better located in the other account type?
- Donate appreciated stock to charity before year-end: Donation must be completed by December 31
- Charitable donations: Verify completion date for charitable giving carryforward or current year deduction
- Check NIIT exposure: Will any year-end gain push MAGI above $200K/$250K?
Loss Harvesting Priority Matrix
Capital loss offset priority and benefit
| Type of Loss | What It Offsets First | Benefit Level |
|---|---|---|
| Short-term losses | Short-term gains (up to 37% rate) | Highest — offset highest-rate gains |
| Long-term losses | Long-term gains (15-20% rate) | High — offset long-term gains |
| Net capital losses | Ordinary income up to $3,000/year | Moderate — cash value of $660-$1,110 |
| Excess net losses | Carry forward to future years | Deferred value — may be used indefinitely |
Stock and ETF trades settle T+2 (2 business days after the trade date). To realize a gain or loss on December 31, the trade must execute on or before December 29. Check your brokerage’s year-end trade deadline for settlements. Mutual fund sales settle T+1 or same day for most funds. Do not wait until December 31 to execute year-end tax trades.
High-Priority Items for 2025 Year-End
The most time-sensitive 2025 capital gains tax actions: (1) Any loss harvesting must be executed by December 29 (settlement by December 31). (2) Charitable stock donations must be received by the charity by December 31. (3) 1031 exchange replacements with a 180-day deadline: verify closing is on track. (4) Required Minimum Distributions from IRA accounts: must be taken by December 31 if you are 73+, affecting your overall taxable income and capital gains rate.
Run Your Year-End Capital Gains Projection
Enter your year-to-date gains and potential loss harvests to see your optimal year-end tax position.