Direct Indexing with ISOs and AMT

Incentive stock options (ISOs) offer a powerful tax advantage: no regular income tax at exercise. The catch: the bargain element at exercise is an AMT preference item that can generate a six-figure AMT bill. Direct indexing cannot erase that AMT cost — but it directly addresses the other half of the ISO equation: the large long-term capital gain at qualifying disposition. This guide covers both, with 2026 AMT figures and a worked example.

How ISO taxation works

ISOs go through three distinct tax events. Each has a different character, and a different interaction with direct indexing.

Qualifying disposition requires both: (1) at least one year from the exercise date and (2) at least two years from the grant date — simultaneously.¹ Missing either threshold converts the sale to a disqualifying disposition, collapsing the tax advantage.

The $100,000 annual limit. Under IRC § 422(d), the aggregate fair market value (measured at grant date) of ISOs that first become exercisable by any employee in a calendar year is capped at $100,000.¹ Any excess is automatically reclassified as a nonqualified stock option (NSO). NSOs trigger ordinary W-2 income at exercise on the full spread — no AMT election involved, and no qualifying-disposition treatment available. Senior employees with large grants often have a split: the first $100K FMV in ISOs, the rest as NSOs.

The AMT trap at exercise

The ISO's main tax benefit — deferring income recognition until sale — has an unintended cost under the Alternative Minimum Tax. When you exercise ISOs, the bargain element is added to your Alternative Minimum Taxable Income (AMTI) as a preference item under IRC § 56(b)(3).² This creates income for AMT purposes while generating none for regular tax purposes.

The result: you can owe significant AMT in the exercise year despite receiving no cash. Many ISO holders find this out at tax time and face an unexpected bill — sometimes larger than the value of the options exercised at a conservative exit valuation.

There is a silver lining: the AMT paid in the exercise year generates an AMT Minimum Tax Credit (MTC) that can be recovered in future years. See the worked example for how this recovery works.

2026 AMT numbers

The OBBBA (One Big Beautiful Bill Act, July 2025) changed AMT exemption phaseout rules significantly — specifically, the phaseout rate on the MFJ exemption was set to 50% and the MFJ phaseout threshold was fixed at $1,000,000 of AMTI.³

Source: IRS Rev. Proc. 2025-32 (2026 inflation adjustments); OBBBA amendments to IRC § 55(d).

What changed with OBBBA: Before OBBBA, the MFJ phaseout rate was 25%, meaning $1 of exemption was lost for every $4 of AMTI above the threshold. OBBBA raised the rate to 50% — so exemption phases out twice as fast. High-AMTI ISO exercisers (AMTI in the $1M–$1.3M range) lose the $140,200 MFJ exemption more rapidly than before OBBBA. For most ISO exercises where AMTI stays below $1M for MFJ filers, the full exemption still applies.

AMT rate calculation: The first $244,500 of AMTI after the exemption is taxed at 26%. AMTI above $244,500 (after exemption) is taxed at 28%. You only pay AMT if the tentative minimum tax (TMT) exceeds your regular tax liability.

What direct indexing can — and cannot — do for ISO holders

Note on MTC and DI: Capital losses from DI reduce your regular capital gains and your AMT capital gains by the same amount. Since both calculations move in parallel, DI doesn't significantly accelerate or delay MTC recovery. The key MTC recovery event is simply having a high LTCG year (qualifying disposition) where regular tax far exceeds tentative minimum tax — that gap is where MTC gets absorbed.

Three strategies for ISO holders

1. Start a DI account before you exercise

If you anticipate exercising a large ISO grant in 12–24 months, start a DI account now with available liquid capital. Every month the DI portfolio runs before your qualifying disposition is another month of loss accumulation. A $300K DI account at 1.5% annual harvest builds approximately $4,500 per year in realized losses. After 24 months, that's $9,000 available to offset qualifying disposition gains — worth $3,300+ in combined federal+NIIT savings at the 23.8% rate, and more with state taxes.

This is a long-lead strategy. The mistake ISO holders make: waiting until the disposition year to fund a DI account. At that point you have almost no accumulated loss bank, and the DI account is too new to have generated meaningful losses to offset the gain.

2. Fund the DI account with exercise-related cash flows

When you exercise ISOs, you spend cash: the exercise price plus (if you owe AMT) a large April tax payment. That combination can leave accounts depleted. But if you have liquid assets — brokerage accounts, savings, pending bonus — that can be redirected into a DI account post-exercise, you start building the loss bank during the mandatory holding period. The two holding-period years while qualifying for a qualifying disposition are exactly the right timeframe to accumulate DI losses.

Key point: fund the DI account with cash or non-DI-candidate assets (e.g., converting an existing ETF position with low embedded gains). Do not transfer highly appreciated assets into the account — that creates a transition cost and defeats the purpose.

3. Coordinate the disposition year with tax planning

Qualifying ISO dispositions generate large LTCG events that land entirely in one tax year. Unlike RSU vesting (which spreads income over multiple years), a qualifying disposition can dump $500K–$2M+ of LTCG into a single return. The combination of a pre-built DI loss bank, the MTC recovery in that year, and strategic gain acceleration or deferral (which your advisor can model) can significantly reduce the combined tax cost.

For California residents in particular: the 13.3% state rate on LTCG means total effective marginal rates on qualifying ISO dispositions exceed 37%. Every dollar of DI loss is worth $0.37 in state+federal+NIIT savings. At that rate, even a small DI loss bank matters.

Worked example: San Francisco startup executive

Profile: Married software exec, Silicon Valley. $400K household W-2 income. Has 100,000 ISOs from Series C startup, exercise price $3/share. Current 409A fair market value: $13/share. Plans to exercise 30,000 shares. California resident.

Note on the $100K limit: If these options were granted when FMV was $3/share, 30,000 shares have a grant-date FMV of $90,000 — within the $100K annual limit. All 30,000 qualify for ISO treatment.

Exercise year — the AMT hit

Cash outlay in exercise year: $90,000 (exercise price for 30,000 × $3) + ~$61,854 AMT = approximately $151,854 in cash to acquire shares worth $390,000 at current FMV. California has no AMT credit for state purposes, so a separate state AMT analysis may apply.

Holding period — building the loss bank (Years 1–2)

Immediately after exercising, the exec redirects $300K of savings into a Parametric direct indexing account (custom employer-stock exclusion screen enabled — startup is private, so no public shares to screen, but the provision prevents future conflicts if the company IPOs and enters an index). At 1.5% annual TLH on a moderately volatile large-cap portfolio: ~$4,500/year in realized losses. After 24 months of mandatory holding: approximately $9,000 in accumulated losses.

Qualifying disposition — Year 3

The startup IPOs. The exec's shares are worth $23/share. After the lock-up period, sells all 30,000 shares. Both holding conditions are met (>2 years since grant, >1 year since exercise).

MTC recovery in Year 3: The exec now has $600K in LTCG, making regular tax far exceed tentative minimum tax (AMT gain = ($23 − $13) × 30,000 = $300,000, a much smaller AMT calculation). This large excess allows the $61,854 MTC to be substantially recovered on Form 8801 — effectively reversing most of the AMT paid at exercise.

The employer-stock exclusion screen

If your startup eventually IPOs and its shares are included in an index tracked by your DI portfolio, you face the same wash-sale risk as RSU holders: the DI platform may hold your former employer's stock, and any ISO exercise, secondary sale, or RSU-like event could trigger the wash-sale rule (IRC § 1091) and disallow the harvested loss.

The fix is an employer-stock exclusion screen — a configuration that removes the employer's ticker from the DI portfolio entirely. For pre-IPO startups, this isn't a concern today. But it becomes critical at IPO if:

• Your employer's shares enter an index your DI account tracks (e.g., Russell 2000 after listing)
• You hold unexercised ISOs or unvested RSUs that you continue to acquire post-IPO
• You are in a trading window lockup with planned post-lockup sales that interact with the 30-day wash-sale window

For advisor-managed platforms (Parametric, Aperio, Vanguard Personalized Indexing), the employer exclusion can be set with a simple instruction and updated as your situation evolves. For self-directed platforms (Wealthfront, Schwab, Frec), configure this at account setup and update it after IPO.

When to start a DI account relative to ISO exercise

Questions to ask a direct indexing advisor

1. Do you have experience modeling ISO exercise timing across AMT, LTCG, and MTC recovery? This requires coordinating your tax advisor's projections with portfolio construction — not all DI advisors do this level of tax integration.
2. How do you handle the employer-stock wash-sale risk if my company IPOs? You want a concrete plan: at IPO, which index does the stock enter, and how quickly will the exclusion screen be updated?
3. Which platform are you recommending for my situation, and why? Institutional platforms (Parametric, Aperio, VPI) handle cross-account wash-sale monitoring and custom overlays; self-directed platforms (Schwab, Wealthfront, Frec) are simpler but have limited coordination capability. For a complex ISO situation, institutional access usually matters.
4. How do you coordinate with my tax advisor on MTC recovery? MTC recovery requires Form 8801 and precise regular-vs-AMT calculations each year. Your DI advisor and CPA should be communicating, not operating independently.
5. What's the right DI account size relative to my expected qualifying disposition gain? A rough heuristic: target a DI account size where 1.5% × account_size × holding_years ≈ 5–10% of expected LTCG. Below that, the offset is negligible relative to the fee drag.

Does direct indexing reduce AMT at ISO exercise?

No. The AMT preference item at exercise is the bargain element — an ordinary-income-type AMTI adjustment. Capital losses from DI offset capital gains, not AMTI adjustments. DI cannot reduce the exercise-year AMT bill. The place DI helps is at qualifying disposition: the resulting LTCG can be offset by DI-harvested losses dollar-for-dollar.

What is a qualifying ISO disposition?

It requires holding ISO shares for at least one year from exercise AND at least two years from the grant date — both simultaneously. Meet both thresholds and the entire gain is LTCG. Miss either and the bargain element at exercise is recharacterized as ordinary W-2 income (a disqualifying disposition). DI losses offset LTCG but not ordinary income recharacterization, so qualifying disposition treatment is critical to the DI strategy's value.

How does the AMT minimum tax credit work?

AMT paid in the exercise year attributable to the ISO preference item generates an MTC equal to that amount. The credit carries forward indefinitely. You recover it in future years when regular tax exceeds tentative minimum tax — Form 8801. For most ISO holders, the qualifying disposition year provides the best recovery opportunity: your regular LTCG is large while your AMT gain is smaller (AMT basis is FMV at exercise, not the exercise price), creating a large regular-over-AMT excess that absorbs the credit.

What is the $100,000 ISO annual limit?

IRC § 422(d) caps the aggregate FMV at grant date of ISOs first exercisable in any one calendar year at $100,000 per employee. Excess is automatically reclassified as NSOs. For example, options granted when the stock is $5/share: if 25,000 shares vest in one year, that's $125,000 FMV — $25,000 worth converts to NSO treatment. Senior employees with large grants frequently have a hybrid ISO/NSO structure as a result.

Should I start a DI account before or after exercising ISOs?

Before, ideally. The mandatory holding period (1 year from exercise, 2 years from grant) is the perfect DI accumulation window. Starting a DI account before or at the time of exercise gives you 12–24 months to build a loss bank ahead of the qualifying disposition. An account started the same month as the qualifying disposition has almost no accumulated losses to deploy.