I’m a Tax Expert: 9 End-of-Year Tax Moves You Should Make Before Dec. 31

With the Dec. 31 year-end deadline approaching, TurboTax spokesperson Lisa Greene-Lewis lays out nine practical tax moves to lower 2025 tax bills, urging investors and clients to adjust withholding, time income, harvest losses and maximize deductions now. Key actionable items include maxing 401(k) contributions by Dec. 31 (2025 limits: $23,500; $31,000 for ages 50+; $34,750 for ages 60–63), harvesting investment losses (up to $3,000 may offset ordinary income), accelerating or deferring income to manage bracket placement, donating to charities or donor‑advised funds, using FSA balances before they expire and funding HSAs (2025 limits: $4,300 individual/$8,550 family), and claiming family-related credits tied to December eligibility. She also flags time‑limited provisions from the One Big Beautiful Bill — notably a SALT cap increase to $40,000 that phases out by income — and recommends self-employed taxpayers close and reconcile their books; taken together these steps can materially affect taxable income, cash flow and state‑tax exposure but some benefits will phase out after Dec. 31.

Analysis

TurboTax spokesperson Lisa Greene-Lewis lays out nine specific year-end tax actions with a firm Dec. 31 deadline that materially affect 2025 liabilities, emphasizing withholding adjustments, retirement contributions, loss harvesting, income timing and charitable giving. She highlights concrete limits and mechanics: 2025 401(k) contribution limits of $23,500 (with $31,000 for ages 50+ and $34,750 for ages 60–63), HSA limits of $4,300 individual/$8,550 family, and the ability to offset up to $3,000 of ordinary income with capital losses. Greene-Lewis flags new provisions from the One Big Beautiful Bill — notably a temporary SALT cap increase to $40,000 — and warns many benefits and credits phase out at higher incomes or disappear after Dec. 31, creating time sensitivity for qualifying purchases and donations. For employers and the self-employed she recommends reconciling books, closing the year cleanly and verifying contractor payments, while reminding taxpayers to use FSA balances by Dec. 31 and that HSA funding can still be made through April but should be planned now to maximize deductions.

Key Decisions for Investors

• Review and, if needed, adjust your W-4 withholding now to reflect changed income and avoid underpayment penalties or unexpected tax bills in 2026
• Maximize employer 401(k) contributions by Dec. 31 to capture immediate tax deferral and potential employer match (2025 limits: $23,500; $31,000 for 50+; $34,750 for 60–63)
• Harvest realized investment losses before Dec. 31 to offset capital gains and up to $3,000 of ordinary income, but avoid wash-sale pitfalls when rebalancing
• Spend FSA balances by Dec. 31 and consider funding HSAs (limits $4,300 individual/$8,550 family for 2025) while planning charitable donations or donor-advised fund contributions now to lock in deductions before phase-outs
• If self-employed, reconcile and close your books, confirm contractor payments and separate personal and business expenses before year-end to ensure accurate deductions and eligibility for credits