The 2017 Tax Cuts and Jobs Act effectively wiped out AMT for most taxpayers by raising the exemption and phase-out thresholds. If you only have W-2 income and standard deductions, you’re probably never seeing the AMT form again. But if you’re exercising incentive stock options (ISOs) at a private company or pre-IPO startup, AMT is still the single biggest tax trap you can stumble into.
And 2026 adds a new wrinkle: much of TCJA is scheduled to sunset at the end of 2025 (unless extended), which could push AMT exemptions back to 2017 levels. ISO exercise planning in 2026 needs a different calculus than it did in 2020-2024.
Why ISOs Trigger AMT When Regular Tax Doesn’t
When you exercise an ISO and hold the shares (don’t sell same day), there is no regular tax event. You don’t report ordinary income or capital gains because the exercise preserves the long-term capital gains treatment at eventual sale.
But for AMT purposes, the bargain element (FMV at exercise minus strike price) is added to AMTI (Alternative Minimum Taxable Income). This creates a phantom income event that can trigger AMT liability without you ever receiving cash.
The $150k Income Trap
Most AMT articles say “AMT affects high earners.” That’s backward for ISO exercisers. It’s actually the mid-income exerciser who gets hit hardest.
Why: the AMT exemption phases out at very high income (over $609k MFJ in 2026), so truly high earners lose the exemption but also hit the 28% AMT rate that’s comparable to their regular marginal rate. For them the gap is smaller.
At $150k-250k income, you still have full AMT exemption, but a big bargain element can catapult AMTI past the exemption and into the 28% bracket, while your regular tax stays in the 24% bracket. The AMT bite is biggest in this income zone.
Worked Example
Single filer, W-2 income $180k, 2026 AMT exemption ~$88k (if TCJA extends) or ~$56k (if sunset).
- ISO exercise: 10,000 shares, strike $5, FMV $15 → bargain element $100,000
- AMTI: $180k + $100k – exemption = $192k-$224k AMTI
- AMT tentative tax at 26% × $192.4k = $50k
- Regular tax on $180k: ~$31k (2026 brackets, rough)
- AMT owed = AMT tentative − Regular tax = $19k of unexpected cash tax
On the $100k phantom income, you now owe $19k in cash with nothing realized. If the stock drops by the time you can sell, you’ve paid real tax on paper gains that evaporated.
The 2026 Sunset Risk
If TCJA provisions expire:
- AMT exemption drops from ~$90k (single) to ~$56k
- Exemption phase-out threshold drops from $639k to $156k for single filers
- Result: more exercises trigger AMT, at lower income levels
Exercising early in 2026 under current rules is safer than late 2026 or 2027 if Congress doesn’t extend TCJA. Plan the exercise date accordingly.
Disqualifying Disposition as AMT Reset
There’s an escape hatch: if you sell the ISO shares in the same calendar year as exercise, the bargain element converts to ordinary income for regular tax purposes, and the AMT adjustment is reversed.
This is called a disqualifying disposition. You lose the long-term capital gains treatment, but you also lose the AMT surprise.
When disqualifying makes sense:
- Bargain element is large relative to your regular tax situation
- You need liquidity and can’t hold for LTCG qualifying period (2 years from grant, 1 year from exercise)
- You want certainty over tax arbitrage
This interacts with broader equity compensation planning that high-earning tech employees need to think through.
AMT Credit Recovery: The Multi-Year Strategy
If you do pay AMT on an ISO exercise, the amount becomes an AMT credit you can recover in future years when your regular tax exceeds your tentative AMT.
Recovery typically takes 7-15 years and is unpredictable because it depends on future income patterns. For planning purposes, treat AMT credit as a below-market loan to the IRS, not as cash equivalent.
To maximize AMT credit recovery:
- Track it meticulously on Form 8801
- Avoid generating new AMT adjustments in recovery years
- Accelerate ordinary income in years where you can (Roth conversions, for instance)
Exercise in January, Not December
Timing within the tax year matters. Exercising in January gives you nearly a full year to decide:
- If stock rises and holds: stay long for LTCG treatment
- If stock crashes: do a disqualifying disposition before year-end to reset AMT
Exercising in December forces commitment with almost no recovery window. The optionality of an early-year exercise is worth real dollars.
Multi-Tranche Exercise Strategy
Rather than exercising all vested ISOs at once, exercise up to the AMT breakeven point each year. Calculate the bargain element that keeps you just at or below the AMT exemption, and exercise that amount annually.
This spreads the AMT cost, preserves the long-term capital gains clock for each tranche, and avoids a single catastrophic AMT year. It’s the most common strategy among sophisticated ISO holders.
What to Do Before Exercising
- Pull last year’s tax return and run a 2026 projection with the bargain element added.
- Calculate AMT liability using both current-law AMT thresholds and sunset scenarios.
- Decide: exercise incrementally, exercise fully and pay AMT, or do a planned disqualifying disposition.
- Build an AMT credit tracking spreadsheet if you do pay AMT.
- Coordinate with other tax moves — Roth conversions, charitable bunching — that interact with AMTI.
ISO exercises are one of the only areas where AMT remains a live issue for non-ultra-wealthy taxpayers. The planning window is before you pull the trigger, not after. Once the exercise is dated, most of the tax math is locked in.