How to Calculate ISO Alternative Minimum Tax (AMT) 2022

What is AMT tax?

The Alternative Minimum Tax (AMT) can apply to current and former employees of privately held companies when they exercise their incentive stock options (ISOs) if the fair market value is higher than the exercise price. The AMT tax can have a significant cash impact on those who exercise their ISOs.


The purpose of AMT is to ensure higher income taxpayers pay their fair share of taxes despite certain preferential deductions that may be available. The three main triggers of AMT are having high household income with a significant number of deductions, realizing a large capital gain, or most commonly exercising stock options. Exercising ISOs can be subject to AMT if there is a significant on-paper gain ( [FMV - Strike Price] * Total ISOs ).

The 2022 AMT exemption amounts are as follows:

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What these exemptions mean for the year 2022 is that if your phantom income from your ISO exercise is less than $75,900 for individuals (or $118,100 for married filing jointly), you may not owe any AMT at all.

The Federal AMT rate is 26% or 28% depending on where your AMT income level falls. The income in the calculation includes normal income plus any ISO exercise gain minus the AMT exemption amount. This creates your adjusted gross income (AGI). State rates vary, but most states have 0 AMT. California for example has an AMT rate of 7%. Other states that have AMT rates are: Iowa (7%), Minnesota (5.8%), and Colorado (3.47%).

Below, go ahead and try out our simple AMT tax calculator that only needs a few inputs (number of options, strike price, fair market value, income level, state, and marriage status). Feel free to reach out if you have any questions!

For questions regarding this AMT Calculator, please contact us through our Intercom chat in the bottom right corner of your screen. If we are away, feel free to email: jordan@esofund.com

How this calculator works:

1. Begins with Total Income
2. Subtracts the 2022 Standard Deduction
3. Calculates Regular Income Tax based on the value from #2 and your state/filing status
4. Calculates ISO spread from the number of options, strike price, and FMV
5. Adds ISO spread to Total Income to arrive at Alternative Minimum Tax Income (AMTI)
6. Subtracts 2022 AMT Exemption
7. Calculates AMT based on #6 and your state/filing status
8. If AMT (#7) is greater than Regular Income Tax (#3) then AMT = AMT-Regular Income Tax. If not, you likely do not owe any AMT!

How to Calculate Alternative Minimum Tax (AMT) When Exercising ISOs:

First calculate your taxes without the ISO exercise. You can use a tax software program such as Turbo Tax Premier or Turbo Tax Home & Business for free as long as you don't file the return. As of this writing, Turbo Tax Deluxe does not seem to have the necessary functionality. If you use Turbo Tax, there will be a question similar to, "Did you exercise and hold Incentive Stock Options During the Tax Year?" You should answer "No" to this question for now. Now take the following steps:

1. Note your total tax amount $ for both state and federal. This is your baseline tax.
2. Now enter an ISO exercise by going back to the question where you initially said No. This time say Yes.
3. Enter the number of shares, exercise price, and Fair Market Value at the time of the exercise. Normally, you would be entering this information from IRS Form 3921 which your company would have sent you in January of the year following your exercise.
4. Upon submitting that ISO exercise event, your total taxes for both Federal and State should immediately update.
5. The difference, if any, between this updated tax figure and your baseline taxes noted earlier (1) is the AMT tax associated with your ISO exercise.
6. Let your ESO Partner know this figure if you want ESO to include this amount in your funding.
7. To calculate how many ISOs you can exercise each year without triggering AMT tax, enter a smaller number of shares in (3) and gradually increase it until your tax due actually increases over the baseline calculation.

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Note that tax rates can change between the time you do this exercise and the time you actually file your return. Moreover, many other factors such as deductions, your tax bracket, state income taxes, and capital gains will also impact your final AMT tax calculation. Since the ESO Fund has no way of knowing how your final taxes will look, you are advised to work with a tax professional to minimize your risk of not having sufficient funds when you finally file your tax return. The ESO Fund is not obligated to increase its funding to you at a later date.

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Below we will dive into Alternative Minimum Tax and how it pertains to the most common trigger: Incentive Stock Option exercises.

ISOs can flip to NSOs

Unlike ISOs, holders of non-qualified stock options (NSOs) are subject to tax at exercise if the fair market value of the stock is higher than the exercise price ("spread"). In contrast, ISO exercises are only subject to AMT which isn't computed until you file your taxes the following April. However, be aware that if you leave a company and negotiate an extension on your exercise period that is longer than 90 days your ISOs will become non-qualified stock options. NSOs are more typically associated with non-employees such as contractors and outside business partners. Moreover, employers are required to withhold at least 25% of the spread at the time of the NSO exercise (like regular income tax). This withholding includes federal, medicare, FICA, and applicable state income taxes. Independent contractors can avoid the mandatory withholding taxes by receiving a 1099 and handling their estimated taxes on their own. However, contractors who were once employees are still subject to mandatory withholding taxes by the company.

Disqualifying Disposition

If the ESO transaction occurs during the same tax year you exercise your ISOs, there could be a substantial tax savings in the form of an AMT Disqualifying Disposition where AMT is eliminated and replaced with tax only on your actual liquidity profits.

AMT Credits and Double Taxation

Another benefit of using ESO proceeds to pay your AMT is having AMT tax credits for subsequent years when you are not subject to AMT. This is a very common result because many people only trigger AMT during the year in which they exercise a large block of stock options. Similarly, letting ESO pay your withholding taxes on an NSO exercise has the indirect benefit of reducing your AMT liability. However, dealing with AMT credits over many years can actually be a burdensome form of double taxation since you are still subject to capital gains taxes at your final sale. Having let ESO fund the extra AMT can be a welcome relief compared to paying taxes twice on the same stock.

Letting ESO Fund the Exercise and Taxes

Since the cost of exercising stock options is already very high, the addition of taxes makes the entire investment even more risky. A solution for reducing this risk is obtaining funding from the ESO Fund to cover the entire cost of exercising your stock options, including the tax. You retain unlimited upside potential without risking any of your personal capital. If you exercised your ISO stock options earlier this year and are concerned with the tax burden next year, then ESO is an ideal solution since we can provide money for the AMT and for the cost of the original exercise.

Fast Approval Process

You retain title to the stock in an ESO transaction. Since you don't have to transfer the stock or pledge it as collateral, this greatly simplifies the paperwork needed to obtain funding from ESO. You also retain the ability to pay off ESO at any time before the company exits. For more information on reducing stock option taxes or regarding how ESO can benefit you, please contact us.

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