High-Income Tax Strategies for U.S. Taxpayers
2026 NIIT · IRMAA · LTCG · Charitable Planning

Overview

High-income taxpayers face a distinct set of tax challenges: the 37% ordinary income bracket, the 3.8% NIIT surtax, the 0.9% Additional Medicare Tax, IRMAA Medicare premium surcharges, and phase-outs of valuable credits and deductions. But they also have access to the most powerful planning tools available in the U.S. tax code.

In 2026, OBBBA changes significantly affect high-income strategy: charitable deductions now carry a 0.5% AGI floor and a 35 cents per dollar cap at the 37% bracket; SALT rose to $40,400; the Mega Backdoor Roth total limit increased to $72,000. The NIIT thresholds remain frozen at $200,000/$250,000 — unchanged since 2013, meaning bracket creep continuously expands NIIT exposure as wages rise with inflation.

NIIT & Additional Medicare Tax

Two separate surtaxes apply above specific MAGI thresholds, independent of regular income tax brackets. Both are added to regular tax on Form 1040.

What Triggers NIIT — and What Does Not

Long-Term Capital Gains — 2026 Brackets

Long-term capital gains (assets held more than 12 months) are taxed at preferential rates: 0%, 15%, or 20%, depending on taxable income. LTCG stacks on top of ordinary income for bracket placement — ordinary income fills the brackets first, and LTCG is layered above it.

Medicare IRMAA — 2026 Brackets

IRMAA (Income-Related Monthly Adjustment Amount) is a Medicare Part B and D premium surcharge for beneficiaries whose income exceeds specified thresholds. It uses a two-year lookback — 2026 premiums are based on 2024 MAGI. Income decisions made today determine premiums two years later.

MAGI Control — The Master Strategy

MAGI is the single number that simultaneously determines NIIT applicability, IRMAA tier, Roth IRA eligibility, SALT cap phase-out, IRA deductibility, and education credit eligibility. Every dollar of MAGI reduction moves multiple dials at once — the leverage is highest near threshold boundaries.

MAGI Reduction Tools

• Pre-tax 401(k) / 403(b) / 457(b) contributions ($24,500 + catch-up): Each dollar reduces MAGI and income tax dollar-for-dollar. At the 37% bracket with NIIT, each $1,000 of pre-tax deferral saves up to $378 in combined federal tax.
• HSA contributions ($4,300 self / $8,550 family, 2026): Triple tax benefit — reduces MAGI, grows tax-free, qualified withdrawals tax-free. Invest HSA funds rather than spending annually; treat as a long-term Roth-like vehicle for healthcare costs.
• SEP-IRA / Solo 401(k) for self-employed (up to $72,000): Largest available MAGI reductions for business owners. A $50,000 employer contribution at the 37% bracket saves $18,500 in federal income tax alone.
• Deferred compensation plans (457(b) / NQDC): Defer current income to future potentially lower-rate years while staying below NIIT and IRMAA thresholds in the current year.
• QCDs from IRA (age 70½+, up to $108,000): Excluded from MAGI entirely — reduces NIIT base, IRMAA calculation, Social Security benefit taxation, and bypasses the 0.5% charitable deduction floor.
• Business losses and Real Estate Professional Status: REPS (750+ hours in real estate, 50%+ of work time) allows rental losses to offset ordinary income — removing the passive activity limitation and providing a powerful MAGI reduction tool.

Charitable Strategies — 2026 OBBBA Rules

Two OBBBA restrictions took effect January 1, 2026 for itemized charitable deductions: a 0.5% AGI floor and a 35 cents/dollar cap for 37% bracket taxpayers. Strategic timing and vehicle selection are essential for high-income donors.

Donor-Advised Fund (DAF) Bunching

• Bunch multiple years into one DAF contribution: Donate 3–4 years of planned giving in one lump sum to the DAF. Take the large itemized deduction in Year 1; take the standard deduction in subsequent years while distributing grants annually from the DAF.
• Donate appreciated securities instead of cash: Direct donation of long-term appreciated stock to a DAF or charity avoids capital gains tax on the appreciation entirely. Deduction = FMV. Never sell first and donate cash if the securities are appreciated.
• QCDs for IRA holders: Age 70½+ should route all or most charitable giving through QCDs before taxable account donations. No 0.5% floor, no 35% cap, reduces MAGI directly, satisfies RMD obligations.

Capital Gain & Loss Harvesting

Gain Harvesting — The 0% LTCG Window

• When taxable income falls below $49,450 (single) / $98,900 (MFJ), long-term capital gains are federally tax-free. Use this window to realize gains and reset cost basis at zero federal cost. Best scenarios: early retirement before Social Security, a high-deduction year, or a business loss year.
• Gains increase taxable income and can push above the 0% threshold — calculate precisely how much can be realized before crossing into the 15% bracket.

Loss Harvesting — Systematic Offset

• Capital losses first offset capital gains dollar-for-dollar, then offset up to $3,000 of ordinary income per year. Excess losses carry forward indefinitely with no expiration.
• Harvesting a loss in a year with large realized gains reduces both the LTCG tax rate and the 3.8% NIIT — dual benefit on each dollar of net gain reduced.
• Wash sale rule (IRC §1091): Cannot repurchase a substantially identical security within 30 days before or after the sale. Replace with a similar but not identical position (e.g., SPY with IVV — different S&P 500 ETF providers) to maintain market exposure without losing the deduction.
• Crypto — wash sale does not apply in 2026: The wash sale rule has not been extended to cryptocurrency. Crypto can be sold to harvest a loss and repurchased immediately. OBBBA did not change this.

Retirement Contributions & Backdoor Roth

For high-income taxpayers, maximizing retirement contributions serves dual purposes: building tax-advantaged wealth and reducing current-year MAGI below NIIT and IRMAA thresholds.

Tax-Efficient Investment Structures

• Asset location: Tax-inefficient assets (bonds, REITs, actively managed funds with high turnover) belong in tax-deferred accounts. Tax-efficient assets (index ETFs, muni bonds) belong in taxable accounts. Same allocation, lower annual tax cost.
• ETFs over actively managed mutual funds: ETFs rarely distribute capital gains due to the in-kind creation/redemption mechanism. Active mutual funds distribute capital gains annually regardless of whether the shareholder sold anything — creating unavoidable taxable events.
• Municipal bonds for NIIT reduction: Muni bond interest excluded from both federal income tax and NIIT. At 37% + 3.8%, tax-equivalent yield = muni yield ÷ (1 − 0.408). A 3.5% muni yield equals a 5.91% pre-tax taxable yield. Shifts both income and NIIT liability simultaneously.
• QOZ investments (OBBBA rolling 5-year deferral — permanent): Investing realized capital gains into a Qualified Opportunity Zone fund defers the original gain and excludes QOZ appreciation after the holding period. Valuable for high-income taxpayers after large capital gain events.

Practical Examples

Common Mistakes

• 1 Treating NIIT as unavoidable once income exceeds the threshold. NIIT applies to the lesser of NII or the MAGI excess above the threshold. Pre-tax 401(k), HSA, and other MAGI-reducing contributions can often eliminate NIIT entirely. A couple at $260,000 MAGI eliminates $380 in NIIT — plus $13,812 in income tax — with $57,550 in pre-tax contributions.
• 2 Harvesting capital losses only in December. Year-round monitoring captures losses at deeper levels. Harvested losses offset both capital gains tax and $3,000 of ordinary income annually, with indefinite carryforward — the sooner captured, the sooner they can offset gains in the same year.
• 3 Donating cash instead of appreciated securities. Direct donation of long-term appreciated stock to a charity or DAF avoids capital gains tax on the appreciation entirely. Deduction = FMV. Always donate appreciated positions first — never sell first and donate the after-tax proceeds.
• 4 Not modeling the two-year IRMAA lookback before large income events. Roth conversions, business sales, and large capital gain realizations all affect MAGI — and MAGI in 2026 determines 2028 Medicare premiums. A $1 income difference can cost $1,000+ per person annually. Every significant income event requires explicit IRMAA cliff modeling.
• 5 Not executing the Backdoor Roth IRA. High-income taxpayers who assume Roth contributions are unavailable miss $7,500–$8,600 of annual Roth accumulation. The strategy is fully legal. Clear pre-tax IRA balances into an employer 401(k) to avoid the pro-rata rule, then execute annually.
• 6 Ignoring the 2026 OBBBA charitable restrictions. The 0.5% AGI floor and 35-cent/dollar cap reduce the after-tax value of large charitable gifts at the 37% bracket. High-income donors who have not recalibrated for 2026 are overstating their expected deduction value — a $100,000 donation now saves $33,250 vs. $37,000 in 2025.
• 7 Holding tax-inefficient assets in taxable accounts. Actively managed mutual funds, bond funds, and REITs generate taxable distributions annually regardless of the holder's own transactions. Moving them to tax-deferred accounts and replacing with ETFs in taxable accounts defers years of investment taxation with no change to overall asset allocation.
• 8 Claiming Social Security early, inadvertently raising MAGI. Social Security benefits are up to 85% taxable when MAGI exceeds specific thresholds — pushing investment income above NIIT thresholds and triggering higher IRMAA tiers. Delaying to age 70 creates maximum annual benefit and preserves MAGI space for Roth conversions at lower rates in early retirement years.

Hanmi CPA Insight