Stock Options and RSUs: How Employer Stock Compensation Is Taxed

If part of your paycheck comes in the form of company stock, you are not alone. Equity compensation has become a go-to benefit at most companies, especially in tech and fast-growing startups. The problem is that stock compensation looks simple on paper and becomes very real at tax time.

RSU taxes and stock option taxes come with rules around vesting, selling, and income reporting that can feel overwhelming. This guide breaks it all down in plain English, so you know when stock is taxed, how much you may owe, and what happens when you sell.

Early on, we recommend reviewing the broader Stock Taxes pillar to understand how employer stock fits into your overall tax picture.

What Is Employer Stock Compensation?

Employer stock compensation is a form of pay that gives employees an ownership stake in the company. Instead of receiving only cash, you receive equity that may appreciate over time.

Why do companies offer equity compensation?

Companies use stock compensation to:

• Attract and retain talent
• Align employee incentives with company performance
• Conserve cash while still offering competitive pay

For employees, stock compensation can be valuable, but it carries tax implications that differ significantly from a standard paycheck.

Common types of stock compensation employees receive

The most common types include:

• Restricted stock units (RSUs)
• Stock options, usually ISOs or NSOs
• Other stock awards tied to performance or time

This article focuses solely on RSUs and stock options. ESPPs and non-employer stock investments are covered elsewhere.

What Are Restricted Stock Units (RSUs)?

Restricted stock units are a promise to issue you actual shares of company stock at a future date, subject to certain conditions.

How restricted stock units work

RSUs are not actual stock when granted. They become actual shares only upon vesting. Until then, they are cash equivalents tied to the company's stock price.

Grant date, vesting schedule, and vesting period

Key RSU terms to know:

• Grant date: When the company promises you the stock units
• Vesting schedule: The timeline for earning the stock
• Vesting period: The time you must stay employed or meet criteria

When RSUs vest, the units convert into actual shares.

Single trigger RSUs vs double trigger RSUs

• Single trigger RSUs vest based only on time or performance
• Double-trigger RSUs require vesting criteria plus a liquidity event, like an IPO

For double-trigger RSUs, taxes are not triggered until both conditions are met.

How RSU Taxes Work at Vesting

RSUs are taxed differently from stock options, which is where many employees get tripped up.

RSUs are Taxed When They Vest

RSUs are taxed when they vest, not when they’re granted. At vesting, the fair market value of the shares is treated as wages and included in your W-2 for the year.

The vesting date is the taxable event.

Source: IRS Pub. 525

Fair Market Value and Taxable Income

The fair market value of the shares on the vesting date becomes taxable income. This amount is added to your W-2 and taxed as ordinary income.

For example:

• 100 RSUs vest
• Share price on vesting date is $50
• $5,000 becomes taxable income

Ordinary Income Taxes and Payroll Taxes

RSU income is subject to:

• Ordinary income taxes
• Social Security and Medicare payroll taxes
• Possible state and local taxes

You owe ordinary income tax even if you do not sell the shares.

Why RSUs Are Taxed Differently Than Stock Options

Unlike stock options, RSUs have no purchase price or strike price. You receive shares automatically when they vest, which is why the IRS treats them as income immediately.

83(b) Election: For Restricted Stock Only

The 83(b) election lets you pay ordinary income tax on restricted stock at the grant date rather than at vesting, typically when the stock value is lowest.

Important distinction: The 83(b) election applies to actual restricted stock — NOT to RSUs. This is a common confusion:

• Restricted stock: Actual shares issued at grant, subject to a vesting schedule and forfeiture. You own them (with restrictions) from day one. 83(b) can apply.
• RSUs: A contractual promise to issue shares at vesting. You don't own anything until vesting. 83(b) does NOT apply.

How 83(b) works:

Normally, restricted stock is taxed as ordinary income at each vesting date based on FMV at vesting. With an 83(b) election, you pay ordinary income tax on the full value at grant, and all future appreciation becomes capital gain.

Example:

• Founder receives 1 million shares at $0.01 per share, vesting over 4 years
• With 83(b): Pay ordinary tax on $10,000 at grant. All subsequent appreciation is capital gain
• Without 83(b): Pay ordinary tax on FMV at each vesting date — which could be enormous

Critical deadline: The election must be filed within 30 days of the grant, and the 30 days is calculated strictly. Miss this deadline, and you cannot recover it.

When to file 83(b):

• Stock is currently valued very low (early-stage startups)
• You reasonably expect significant appreciation
• You can afford to pay ordinary income tax now on the current value
• You believe you'll actually vest (don't pay tax on stock you'll forfeit)

How to file: Send a signed 83(b) election to the IRS at the address where you file your tax return, include it with your tax return for that year, and give a copy to your employer. Keep proof of filing.

83(b) elections are not reversible. Consult a tax advisor before filing.

Source: IRC §83(b)

RSU Withholding and Cash Flow Considerations

RSU taxes can create cash flow issues if you are not prepared for the timing.

How employers withhold taxes on RSU income

Most employers withhold federal income tax on RSU income using the IRS supplemental wage rules, often by selling some shares to cover withholding. Depending on your tax bracket, this withholding may not fully cover your total tax owed.

Taxes withheld may not match your actual tax liability.

Federal supplemental withholding defaults:

• Up to $1M in supplemental wages per year: 22%
• Amount exceeding $1M: 37% (mandatory — cannot be reduced)

Why this is a problem:

If you're in the 32%–35% federal marginal bracket, your employer's 22% default withholding is inadequate. On a $100,000 RSU vest:

• Tax withheld at 22%: $22,000
• Actual tax liability at 32%: $32,000
• Underpayment: $10,000

Plus state withholding, which varies. Plus NIIT. Plus Additional Medicare Tax (0.9% above the NIIT thresholds).

Solutions:

• Ask payroll if the supplemental rate can be increased (some employers allow)
• Make quarterly estimated tax payments for the shortfall
• Elect additional W-4 withholding on base salary
• Set aside cash each vesting to cover the gap

Source: IRS Pub. 15, Supplemental Wages

Sell to cover vs shares immediately deposited

With sell to cover:

• Some shares are sold automatically
• Remaining shares are deposited into your brokerage account

With shares immediately deposited, you may need to pay taxes out of pocket.

Why taxes withheld may not cover your full tax liability

If you are in a higher tax bracket, the withholding rate may be too low. This can lead to additional taxes due when you file taxes.

What Happens When You Sell Vested RSU Shares

Selling RSUs creates a second, separate tax event.

Cost basis and fair market value

Your cost basis is the fair market value on the vesting date, which is critical when calculating capital gains or capital losses after you sell. If your cost basis isn’t adjusted to reflect the income already reported on your W-2, you could be taxed twice on the same RSU income when you sell the shares.

Source: IRS Pub. 550, Basis of Investment Property

Capital gains tax vs capital loss

• If you sell above the vesting price, you have capital gains
• If you sell below it, you have a capital loss

Proper reporting matters here. See our Reporting Stock Sales guide to learn how to report RSU and stock option sales using Form 8949 and Schedule D.

Long-term capital gains if you hold more than a year

Holding vested shares for more than a year may qualify you for long-term capital gains treatment, which is typically taxed at lower rates. See the Capital Gains article for more details.

Stock Options Explained: ISOs vs NSOs

Stock options give you the right to buy company stock at a set price.

What stock options are and how they differ from RSUs

Unlike RSUs:

• You must choose to exercise stock options
• You pay a purchase price called the strike price
• Stock options can expire worthless

ISO vs NSO taxes at exercise

• Incentive stock options (ISOs) aren’t taxed at exercise for regular income tax purposes. However, the spread between the strike price and fair market value is included for alternative minimum tax (AMT) calculations, even if you don’t sell the shares.
• Nonqualified stock options (NSOs) are taxed as ordinary income when exercised

Source: IRS Instructions for Form 6251

Strike price, share price, and taxable events

The difference between the strike price and the fair market value at exercise determines taxable income for NSOs.

How Stock Options Are Taxed When You Sell

Selling option shares can create additional taxes.

Ordinary income vs capital gains treatment

For NSOs:

• Ordinary income is recognized at exercise
• Capital gains apply when you sell

For ISOs:

• Capital gains may apply if holding requirements are met

ISO Exercises and the Alternative Minimum Tax (AMT)

Incentive stock options (ISOs) are taxed favorably for regular income tax — no tax is owed at exercise. But the bargain element (fair market value minus strike price) is a preference item for Alternative Minimum Tax (AMT) purposes.

What this means in practice:

If you exercise ISOs with a large bargain element, you may owe substantial AMT even though no ordinary tax is triggered. And you may owe this tax on shares you haven't sold and may not be able to sell (e.g., private company stock).

Simplified AMT calculation:

1. Start with regular taxable income
2. Add back the ISO bargain element (and other AMT preference items)
3. Subtract the AMT exemption (90,400 single / 140,700 MFJ estimated for 2026; phases out at higher incomes)
4. Apply AMT rates (26% up to threshold, 28% above)
5. Compare to regular tax — you pay the higher of the two

Example: You exercise ISOs with a 200,000 bargain element. Your marginal AMT impact could be 52,000+ in the year of exercise, even though you haven't sold any shares.

AMT credit: AMT paid on ISO exercises can generate a credit against future regular tax when you eventually sell the shares (or in later years with lower AMT). The credit can be carried forward indefinitely.

Planning implications:

• Consider exercising early in the year so you can sell in a "disqualifying disposition" before year-end if AMT is problematic
• Spread exercises across multiple tax years to stay below AMT thresholds
• Track AMT basis separately from the regular basis for later sales
• A tax professional should model AMT before any significant ISO exercise

Source: IRS Form 6251 Instructions

ISO Qualifying vs Disqualifying Disposition

How you're taxed on ISO shares when sold depends on when you sell them.

Qualifying disposition:

• Sale occurs more than 2 years after the grant date AND
• More than 1 year after the exercise date
• Result: The entire gain (sale price − strike price) is long-term capital gain

Disqualifying disposition:

• Sale before either of those holding periods are met
• Result: Portion equal to bargain element at exercise becomes ordinary income (added to W-2 for that tax year); remaining gain is short-term or long-term capital gain based on holding period since exercise

Why this matters: Qualifying disposition is the whole point of ISOs — the long-term capital gain treatment is the tax preference. But holding long enough to qualify can expose you to stock price drops, and AMT paid at exercise may not be recoverable if the stock crashes.

Why timing matters for tax implications

Selling the same day vs. holding shares can significantly affect your tax outcome.

Net Investment Income Tax (NIIT) on Employer Stock Sales

High earners who sell RSU or option shares at a gain may owe an additional 3.8% Net Investment Income Tax on top of capital gains tax.

NIIT applies when your Modified Adjusted Gross Income (MAGI) exceeds:

• $200,000 (single, head of household)
• $250,000 (married filing jointly)
• $125,000 (married filing separately)

The 3.8% tax applies to the lesser of your net investment income or the amount your MAGI exceeds the threshold.

For tech employees at mid- to late-stage companies: MAGI often exceeds these thresholds due to the combination of a high salary and vested RSUs. The NIIT on a large stock sale can add $10,000+ to your tax bill.

See our Capital Gains Tax on Stocks guide for full NIIT mechanics, including calculation examples.

RSUs and Stock Options Compared

RSUs and stock options are both forms of equity compensation, but they behave very differently.

RSUs vs ISOs vs NSOs: Tax Comparison

Key tax differences at vesting and exercise

RSUs:

• Taxed as ordinary income at vesting
• No purchase price

Stock options:

• Taxed at exercise or sale
• Depend on strike price and option type

Risk, reward, and cash flow differences

RSUs are lower risk but have guaranteed taxes. Stock options have a higher upside but can expire worthless.

Section 1202: Qualified Small Business Stock (QSBS)

One of the most powerful tax benefits for startup employees and founders is Section 1202, which allows the exclusion of up to $10 million (or 10 times the stock's basis, whichever is greater) of capital gain on qualifying stock sales.

To qualify:

1. Stock must be in a domestic C corporation (not LLC, S corp, or foreign entity)
2. Gross assets of the corporation must be $50 million or less at the time of issuance
3. Stock must be held for at least 5 years
4. Corporation must be engaged in a qualified trade or business (excludes professional services, financial services, hospitality, farming, mining)
5. Stock must be acquired at original issuance (primary issuance from the company, not secondary market)

Exclusion percentages by acquisition date:

• Acquired 8/11/1993 to 2/17/2009: 50% exclusion
• Acquired 2/18/2009 to 9/27/2010: 75% exclusion
• Acquired after 9/28/2010: 100% exclusion (and no AMT preference)

Practical implications:

• This is a huge benefit for early-stage employees at qualified startups
• Many tech employees are eligible but unaware
• Requires careful documentation: prove the company met QSBS criteria at stock issuance
• State treatment varies — California fully conforms, some states don't conform at all

If you received stock in a tech startup, early-stage biotech, or similar company, talk to a tax professional about potential QSBS eligibility before selling.

Source: IRC §1202

How RSU and Stock Option Income Is Reported on Your Tax Return

Proper reporting prevents costly mistakes.

W-2 reporting and taxable income

RSU income and NSO income appear on your W-2 as wages.

Brokerage forms and reporting capital gains

When you sell RSU or option shares, your broker reports the sale on Form 1099-B. You generally report capital gains or losses on Form 8949 and Schedule D. For details, see the Cost Basis article.

For a deeper breakdown, see our Form 1099-B Reporting guide to understand how brokers report stock transactions and what details the IRS receives.

Common mistakes when you file taxes

Common issues include:

• Double reporting RSU income
• Incorrect cost basis
• Forgetting state tax obligations

How to Minimize Taxes on RSUs and Stock Options

You generally can’t avoid taxes on stock compensation, but timing and diversification decisions may affect when and how much tax you owe.

Timing sales with your income

Selling shares in a lower-income year may reduce overall tax liability.

Managing investment portfolio concentration

Holding too much company stock increases risk. Diversifying can improve cash flow and reduce stress.

When to talk to a tax professional

Stock compensation can trigger unexpected taxes. A tax professional can provide specific advice based on your situation.

What RSU and Stock Option Taxes Mean for Your Tax Return

Equity compensation should feel like a win, not a tax surprise. FileTax.com helps you report RSU income, stock option activity, and capital gains correctly without the headache. File with confidence and keep more of what you earn. Visit our Stocks and Taxes page to learn more.