How to navigate new tax rules in year-end planning, according to top-ranked advisors

Taxes have grown more complex amid changes from President Donald Trump's "big beautiful bill" and other updates, which top-ranked advisors say could affect year-end tax planning. The Republicans' marquee legislation extended Trump's 2017 cuts while adding new tax breaks for tip income, overtime earnings and auto loan interest, as well as a deduction that benefits seniors. The law also boosted the federal deduction limit for state and local taxes, known as SALT, among other shifts. Often, planning happens throughout the year, and most strategies must be completed by Dec. 31 to affect tax refunds or balances due for the ensuing tax filing season. As year-end approaches, there are some key tax moves to consider, experts say. Manage income for the 'ACA cliff' Changes to adjusted gross income, or AGI, can affect a range of tax benefits, including the premium tax credit, which makes Affordable Care Act marketplace health insurance cheaper. While Congress boosted the credit during the pandemic, the enhanced benefit expired after 2025, exposing millions of Americans to the so-called "ACA cliff" starting in 2026. That means if they earn even $1 more than a certain income threshold, they lose all eligibility for subsidies and must pay the full premium for health coverage. "This is the first year the ACA cliff really matters," said Tommy Lucas, a certified financial planner at Moisand Fitzgerald Tamayo in Orlando, Florida. His firm is ranked No. 44 on CNBC's Financial Advisor 100 list for 2026. The cliff affects ACA enrollees once household income exceeds 400% of the federal poverty line threshold, which varies by family size. For 2026, those limits are about $63,000 for a single person or $129,000 for a family of four. But there are strategies to avoid "falling off the cliff," such as pairing a high-deduction health plan with health savings account contributions, which reduce your AGI, Lucas said. Leverage the charitable deduction Starting in 2026, Trump's legislation also added a charitable deduction for filers who don't itemize tax breaks, worth up to $1,000 for single filers and $2,000 for married couples. The deduction applies to cash contributions made to eligible nonprofit organizations. A $2,000 deduction reduces your income subject to tax. For example, if a married couple filing jointly in the 22% tax bracket donates $2,000, they could reduce federal income taxes by up to $440. If you claim the deduction for 2026, you could have "a little bit more room" to potentially offset moves that add to your taxable income, such as selling profitable investments or making Roth conversions, Lucas said. Transfer assets to a donor-advised fund If you itemize deductions and give to charity, Trump's legislation added two changes that could reduce your benefit. For 2026, there's a charitable deduction "floor" for itemizers, which allows the tax break only once your donations exceed 0.5% of AGI. There wasn't a floor before the 2025 tax law. For example, if your AGI is $200,000 and you donate $10,000 in 2026, the 0.5% floor, or the first $1,000, isn't eligible for the charitable deduction. Trump's legislation also limits the deduction for top-earning households in the 37% top marginal income tax rate by effectively capping the tax break at 35%. With the S&P 500 hovering near a record high, many investors are sitting on profitable assets in taxable brokerage accounts and may consider donating those assets for a possible charitable deduction. One way to maximize gifts under the new law is bunching charitable gifts you'd have otherwise donated gradually into a single year, according to CFP Charissa Anderson, an executive vice president at Ferguson Wellman Capital Management in Portland, Oregon. Her firm ranked No. 52 on CNBC's Financial Advisor 100 list for 2026. "Bunching becomes even more tax-effective when we pair it with the donor-advised fund and fund it with appreciated stock," she said. Donor-advised funds work like a charitable checkbook, allowing taxpayers to make a large gift at one time but can distribute the funds to eligible nonprofit organizations over time. Plus, donating profitable investments "still continues to provide the benefits of avoiding capital gains," Anderson said. CNBC receives no compensation from placing financial advisory firms on our Financial Advisor 100 list. Additionally, a firm's or advisor's appearance in our ranking does not constitute an individual endorsement by CNBC of any firm or advisor.