The $10,000 SALT cap that frustrated taxpayers in high-tax states since 2018 just became $40,000 — at least for now. The One Big Beautiful Bill Act (OBBBA) quadrupled the state and local tax deduction limit for tax years 2025 through 2029, giving millions of itemizing taxpayers a meaningful reduction in taxable income. But the change comes with a sharp phaseout that creates one of the most punishing effective tax rates in the code for earners between $500,000 and $600,000.
What Is the SALT Deduction?
The state and local tax (SALT) deduction lets itemizers subtract certain state and local taxes paid during the year from their federal taxable income. Three categories qualify:
- State and local property taxes on real and personal property
- State and local income taxes paid during the year (including estimated payments)
- State and local general sales taxes — but only as a substitute for income taxes, not in addition
You must choose between deducting state income taxes or state sales taxes — not both. Most taxpayers in states with an income tax benefit more from deducting income taxes. Taxpayers in states without one — Texas, Florida, Washington — can deduct sales taxes using the IRS Optional Sales Tax Tables.
The SALT deduction lives on Schedule A. You must itemize to claim it. If you take the standard deduction ($31,500 MFJ for 2025), the SALT deduction has no effect on your federal return.
The New Cap Schedule: 2025–2030
The cap increases by 1% annually through 2029, and the $500,000 phaseout threshold increases by 1% annually as well. Beginning in 2030, the deduction reverts to a permanent $10,000 — regardless of income — unless Congress acts again.
The Phaseout: Who Gets the Full $40,000?
For taxpayers with MAGI above $500,000, the deduction cap shrinks by $300 for every $1,000 of excess MAGI (30 cents per dollar). The cap cannot fall below the $10,000 floor — so taxpayers at or above $600,000 MAGI get the same $10,000 they had under the TCJA.
For most domestic filers, MAGI equals AGI (Form 1040, Line 11). Adjustments apply only for foreign earned income exclusion and certain U.S. possession income.
2025 SALT Cap by MAGI (Single or MFJ)
Phaseout TableMAGI ≤ $500,000 → Full $40,000 cap
MAGI = $520,000 → $34,000 cap ($40,000 − 30% × $20,000)
MAGI = $540,000 → $28,000 cap ($40,000 − 30% × $40,000)
MAGI = $560,000 → $22,000 cap ($40,000 − 30% × $60,000)
MAGI = $580,000 → $16,000 cap ($40,000 − 30% × $80,000)
MAGI ≥ $600,000 → $10,000 floor
Important: the phaseout threshold is not doubled for joint filers. A married couple filing jointly and a single filer both face the same $500,000 trigger. For dual-income households, this can accelerate the phaseout unexpectedly when two solid incomes combine.
The SALT Torpedo: A 45.5% Effective Rate
The phaseout creates a hidden tax trap for earners between $500,000 and $600,000. Earning an extra dollar of income doesn't just add one dollar of taxable income — it also reduces your SALT deduction by $0.30, adding another $0.30 to taxable income. That compounds the impact.
Concrete example: A taxpayer at $500,000 MAGI receives a $100,000 bonus, pushing MAGI to $600,000. They don't just add $100,000 to taxable income — they also lose $30,000 of SALT deduction ($100,000 × 30%). Total taxable income increase: $130,000. At the 35% marginal rate, the tax bill increases by $45,500 — a 45.5% effective rate on that $100,000.
This is the SALT Torpedo: income in the phaseout band faces a marginal rate nearly 30% higher than the statutory bracket. It's one of the steepest implicit rate cliffs in the 2025 code.
Is It Now Worth Itemizing?
With the standard deduction at $31,500 (MFJ) and $15,750 (single) for 2025, some taxpayers who took the standard deduction in recent years may now find itemizing beneficial. The break-even depends on total deductions.
Itemizing likely wins when:
- Your combined SALT exceeds $20,000–$25,000 and you also have mortgage interest or charitable contributions
- As a married couple, your state income taxes plus property taxes approach $31,500 without other deductions
Standard deduction still wins when:
- You live in a low-tax state with modest property taxes (total SALT under $10,000–$12,000)
- You have minimal mortgage interest and limited charitable giving
- You're a single filer with limited state taxes — $15,750 remains a high bar for one person
If you were borderline under the old $10,000 cap, run the math again for 2025. The jump to $40,000 may have changed your answer.
Planning Strategies
Control MAGI Below the $500K Threshold
If your MAGI is near $500,000, prioritize strategies that reduce it before year-end. Maximize pre-tax retirement contributions (401(k), SEP-IRA, or a defined benefit plan for self-employed), contribute to an HSA, and harvest capital losses to offset realized gains. Avoid discretionary Roth conversions or large asset sales in the same year. Each $1,000 below $500,000 preserves $300 of SALT deduction — a guaranteed 30% return on income deferral.
Use a Pass-Through Entity Tax (PTET) Election
State taxes paid at the entity level through a PTET election are deducted as a business expense — entirely outside the SALT cap. For pass-through business owners in states offering PTET (most states now do), this effectively bypasses the $40,000 cap. Even with the higher cap, PTET remains valuable for owners whose state taxes exceed $40,000 or who are in the phaseout range above $500,000. The OBBBA explicitly preserved PTET workarounds.
Prepay Assessed Property Taxes
If your jurisdiction has assessed and billed your 2026 property taxes by December 31, 2025, you can prepay them and claim the deduction on your 2025 return — locking in a year with the $40,000 cap before the 2030 reversion. This strategy only works for taxes already assessed; you cannot deduct estimated future taxes that haven't been billed. Verify with your county assessor before year-end.
Pair SALT With a Donor-Advised Fund
If your SALT is large enough to push you into itemizing territory but other deductions are thin, consider accelerating charitable contributions into a donor-advised fund (DAF). A DAF lets you take a large upfront deduction in 2025 and distribute grants to charities over multiple years. Stacking a significant DAF contribution with your full SALT deduction can eliminate substantial taxable income in the years the $40,000 cap applies.
AMT Warning: SALT Doesn't Survive the Alternative Minimum Tax
State and local taxes are not deductible for Alternative Minimum Tax (AMT) purposes. If you're subject to the AMT, your SALT deduction on Schedule A is added back in computing Alternative Minimum Taxable Income (AMTI).
The OBBBA adjusted the AMT exemption phaseout starting in 2026, which may increase AMT exposure for some high-income joint filers. If you have significant SALT, large investment preference items, or incentive stock option exercises planned, AMT analysis is essential before claiming a large SALT deduction. In some cases, the AMT will claw back the entire benefit — making the deduction strategy meaningless.
State Tax Conformity: Not All States Follow Federal Law
Many states do not automatically adopt OBBBA provisions. New Jersey, for example, confirmed it does not conform to the new federal deductions. California and New York have their own taxable income definitions that may diverge from the federal Schedule A treatment.
This matters because state returns are often prepared from federal AGI or federal taxable income as a starting point. Claiming the full $40,000 SALT deduction federally does not mean your state return reflects the same numbers — and some states may require addbacks for OBBBA deductions taken elsewhere on the federal return. State-by-state analysis is required, not assumed conformity.
The 2030 Sunset: A Window That Closes
The $40,000 cap is temporary. Without new legislation, SALT reverts to $10,000 in 2030. For high-income taxpayers in high-tax states, the 2025–2029 window creates real planning opportunities: accelerating state tax payments where possible, structuring asset sales to benefit from years of maximum deductibility, and building charitable giving strategies around years with elevated SALT.
Multi-year modeling — not just annual return prep — captures the most value from this temporary change.
Whether you're itemizing for the first time in years or managing income near the $500,000 phaseout threshold, the SALT changes require careful analysis alongside your overall tax picture. Contact TS CPA to model the phaseout impact on your specific situation and identify the strategies that reduce your 2025 and 2026 tax liability.