VIP Financial Insights | Expert Wealth & Tax Strategies for High Earners

ISOs and the New AMT Cliff | Tax Strategy for High-Income Professionals in 2025

Written by Mark Stancato, CFP®, EA, ECA, CRPS® | Jul 8, 2025 1:52:26 PM

 

When Congress passed the One Big Beautiful Bill in July 2025, headlines focused on splashy headlines—like lifting the SALT cap and eliminating taxes on tips. But quietly tucked inside was a profound change to an often misunderstood tax mechanism: the Alternative Minimum Tax (AMT).

If you've ever exercised incentive stock options (ISOs), held municipal bonds, or claimed large deductions, the AMT may have blindsided you. The new law doesn't eliminate AMT, but it does fundamentally rewrite how it works for high-income earners.

Let's break down what's changed, why it matters, and what high earners—especially those with equity compensation—need to do now.

🔍 A Quick Refresher on AMT

The AMT was created in 1969 to ensure wealthy taxpayers couldn't zero out their tax bill using aggressive deductions or shelters. It created a parallel tax system that adds back “preference items” and removes many common deductions. If your AMT is higher than your regular tax, you pay the higher amount.

Common AMT triggers include:

  • Exercising ISOs and holding the stock past year-end
  • Large deductions for state and local taxes (SALT)
  • Tax-exempt interest from private activity bonds
  • Accelerated depreciation on business assets

The AMT became increasingly painful over time because it wasn't originally indexed to inflation. That dragged more upper-middle-class professionals—especially those in tech, finance, and real estate—into its net.

The 2017 Tax Cuts and Jobs Act (TCJA) temporarily raised the AMT exemption and phaseout thresholds, sparing many taxpayers. But that relief was set to expire after 2025.

The One Big Beautiful Bill locks in higher exemption levels—and introduces new limits that create both planning opportunities and new tax cliffs.

📜 Key Changes to the AMT in 2025 and Beyond

1. Higher Exemptions Made Permanent

Starting in 2026, the elevated AMT exemptions are now permanent:

  • $137,000 for married filing jointly
  • $88,100 for single filers

These amounts shield many from AMT—unless they have significant preference income, such as ISO exercises.

2. Lower Phaseout Thresholds

Here's the major shift. The exemption doesn't last forever—it phases out at certain income levels. Under the old rules, which started at:

  • ~$1,252,700 for MFJ
  • ~$626,350 for Single

Under the new law, starting in 2026:

  • $1,000,000 for married filing jointly
  • $500,000 for single filers

That's a drop for both groups, and it means more high earners will start losing their exemption sooner.

3. Phaseout Rate Doubles

Once you reach those thresholds, your exemption disappears more quickly. The rate increases from 25% to 50%—so for every $1 you earn over the threshold, you lose $0.50 of exemption.

4. Inflation Indexing Resumes

Beginning in 2027, the phaseout thresholds will be indexed for inflation again, but starting from this new, lower 2025 base.

5. Effective Date + Planning Window

These changes will take effect in 2026. If you're planning a major income event—like exercising options or selling a business—timing it in 2025 vs. 2026 could significantly impact your AMT exposure.

💡 What This Means for High Earners

The AMT may no longer be a mystery, but it's now more aggressive and less forgiving, especially for high earners with lumpy incomes.

🔻 Both Single and Married Filers Take a Hit

  • Single filers see the exemption begin to phase out earlier and disappear faster.
  • Married couples lose the previous advantage of a higher threshold and now face the same steep 50% erosion rate.

This creates a new AMT cliff, where crossing a narrow income band can wipe out thousands in exemption and trigger unexpected liability.

If you're:

  • Exercising ISOs
  • Selling a business
  • Realizing long-term capital gains
  • Vesting large RSU grants or deferred comp

...then how and when you recognize that income has never mattered more.

🔴 More Complexity for Equity Compensation

If you hold Incentive Stock Options (ISOs), these new AMT rules are especially important.

Exercising ISOs and holding the stock past year-end creates AMT income, even if you haven't sold the shares. And that income can push you past the new phaseout threshold faster than ever.

Here's what to watch:

  • Single filers start losing their exemption at $500K AMTI
  • Married filers begin phaseout at $1M AMTI
  • Everyone loses exemption at $0.50 per dollar over the limit

Implication: Even moderate ISO exercises can cause disproportionate AMT liability if not carefully modeled. What worked last year may blow up in 2026.

🧠 Strategic Planning Moves to Make Now

Here's how we're helping VIP clients adjust:

1. Model Before You Exercise ISOs

We run AMT simulations to compare what happens if you exercise in 2025 vs. 2026 and beyond. With a sharper phaseout curve, precise modeling is essential.

2. Break Up Big Income Events

Selling a business? Vesting large RSUs? Break that income across multiple years when possible. Staying below the exemption cliff can reduce AMT exposure dramatically.

3. Reassess Municipal Bond Strategy

Private activity bonds can trigger AMT. If you're near the new thresholds, you may need to rethink your allocation.

4. Use AMT Credit Carryforwards Strategically

If you've paid AMT in previous years, you may be entitled to a credit. With lower exemption thresholds ahead, smart planning around when to use those credits is crucial.

🎯 Final Word

The AMT has always been a stealth tax, easy to overlook until it significantly impacts your cash flow in a high-income year.

The 2025 law didn't kill AMT. It rebuilt it with a sharper cliff, a steeper phaseout, and a tighter room for error, especially for high earners with equity compensation or multi-source income.

At VIP Wealth Advisors, we're already helping clients restructure ISO timing, rebalance investment strategies, and prepare for a more complex AMT environment.

If you're navigating seven-figure income decisions, this isn't the year to wing it.

Looking for expert guidance on equity compensation, tax strategy, and advanced planning? Book your complimentary discovery call and see how VIP Wealth Advisors can help.