How NSOs Are Taxed: Ordinary Income at Exercise, Then Gains

Priya, a 34-year-old senior engineer in Austin, exercised 10,000 NSOs in 2026. Her strike was $10; the fair market value on exercise day was $30. That $200,000 spread (($30 − $10) × 10,000) landed on her W-2 as ordinary compensation income. As a single filer at roughly $180,000 of base salary in no-income-tax Texas, the spread pushed her top dollars into the 35% federal bracket, and she owed FICA on top. Her question was the one almost every NSO holder asks: am I being taxed twice? The answer is no — but the way the two taxable moments stack determines whether her eventual sale costs her 15% or 35%, and that single timing choice is worth about $40,000 to her.

The two taxable moments — and the one that isn’t

An NSO (non-qualified stock option) gives you the right to buy company stock at a fixed strike price (also called the grant or exercise price). There are three events in an option’s life, and only two of them are taxable:

• Grant — not taxable. Receiving the option is a non-event for tax. (NSOs are granted at FMV, so there is no “bargain element” to tax at grant under IRC §83.)
• Exercise — ordinary income. When you buy the shares, the spread (FMV at exercise − strike) × shares is ordinary compensation income. It hits your W-2 and is subject to federal income tax, Social Security, and Medicare.
• Sale — capital gain or loss. When you later sell, any move above the exercise-date FMV is a capital gain (or loss). Short-term and taxed as ordinary income if you held under a year; long-term at 0/15/20% if you held longer.

The reason it is not double taxation: the spread you already paid ordinary tax on becomes part of your cost basis. Under IRC §83(a), the amount included in income at exercise is added to what you paid (the strike), so your basis equals the exercise-date FMV. Only the appreciation after that point gets taxed a second time, and only as capital gain. Each dollar is taxed exactly once.

Step 1: tax at exercise (the ordinary-income layer)

The moment you exercise, the formula is simple:

NSO ordinary income = (FMV at exercise − strike price) × number of shares.

That number is added to your wages. It is taxed at your marginal federal bracket — for 2026 that means the 32% bracket starts at $197,301 (single) and 35% at $250,526 (single). It is also subject to FICA, which surprises people who assume options escape payroll tax:

• Social Security: 6.2% up to the 2026 wage base of $181,800 (so once your wages exceed that, no further Social Security on the spread).
• Medicare: 1.45% on the entire spread, with no cap.
• Additional Medicare tax: 0.9% on wages above $200,000 (single) / $250,000 (MFJ) under IRC §3101(b)(2).

Your employer is required to withhold. Federal supplemental withholding on the spread is a flat 22% up to $1 million of supplemental wages in the year, and 37% on any portion above $1 million (IRS Pub. 15). That 22% is the trap: if your spread pushes you into the 32% or 35% bracket, 22% withholding leaves you under-withheld, and you owe the rest at filing. On a $200,000 spread, the gap between 22% withheld and a 35% marginal rate is up to $26,000 you must cover with estimated taxes or at filing.

What “FMV” means for a private company

For public companies, FMV is the market price on exercise day. For private companies, FMV is the most recent 409A valuation — an independent appraisal under IRC §409A. That matters because exercising a private NSO can generate a large, real, cash-out-of-pocket tax bill on a paper gain you cannot yet sell to fund. Always confirm the current 409A FMV before exercising private shares.

Step 2: tax at sale (the capital-gains layer)

When you sell, you compute a capital gain or loss from your reset basis:

Capital gain = sale price − exercise-date FMV (your basis).

The holding period for capital-gains purposes starts the day after exercise — not grant. So:

• Sold 1 year or less after exercise: short-term capital gain, taxed at ordinary rates (up to 37%).
• Sold more than 1 year after exercise: long-term capital gain at 0%, 15%, or 20% (IRC §1(h)), plus the 3.8% Net Investment Income Tax on amounts over $200K (single) / $250K (MFJ) MAGI under IRC §1411.

For 2026, the 15% long-term rate runs from $48,351 to $533,400 of taxable income (single); above $533,400 the rate is 20%. Most NSO holders selling a normal position land in the 15% band, with NIIT bringing the effective top to 18.8% or, at the very top, 23.8%.

Worked example: Priya’s $200K spread, two ways

Back to Priya. Strike $10, FMV at exercise $30, 10,000 shares. Spread = $200,000 of ordinary income at exercise either way. The question is what happens when she sells at $50/share ($500,000 total), producing $200,000 of post-exercise appreciation ($50 − $30 = $20 × 10,000). She is a single filer in Texas (no state income tax), already at the 35% federal margin on her top dollars.

Holding one extra year converts the $200,000 of appreciation from a 35% ordinary rate to a 15% long-term rate — saving roughly $40,000. (At the very top of the brackets the gap is even larger once you add the 3.8% NIIT on the short-term side as well.) The ordinary-income layer on the spread is unavoidable; the capital-gains layer is where the decision lives.

NSO vs. ISO in one line

If you are not sure which type you hold, check your grant document — it will say “non-qualified”/“NSO”/“NQSO” or “incentive”/“ISO.” The one-line difference: an NSO spread is ordinary W-2 income plus FICA at exercise, while an ISO spread is generally not regular-tax income at exercise but is an AMT preference item (IRC §56(b)(3)) that can trigger the alternative minimum tax. ISOs can reach 100% long-term rates if you meet the two holding tests; NSOs always carry the ordinary-income hit on the spread no matter how long you hold. If you hold both, the exercise order matters — see the linked NSO-vs-ISO order guide.

What most people miss: the double-counted basis on Form 8949

This is the single most expensive NSO mistake, and it shows up at sale, not exercise. When your broker issues Form 1099-B, it frequently reports your cost basis as the strike price only — not the exercise-date FMV. Using Priya’s numbers, the broker may report basis as $10/share ($100,000) instead of the correct $30/share ($300,000).

If you (or your tax software) accept that figure, you report a $400,000 gain on the sale instead of the correct $200,000 — meaning you pay capital-gains tax a second time on the $200,000 spread you already paid ordinary income tax on at exercise. That is real double taxation, caused entirely by a reporting quirk, and it is easy to miss.

The fix: on Form 8949, use code B in column (f) and enter the basis adjustment in column (g) to bring your basis up to the true exercise-date FMV. Cross-check against the “Code V” amount in Box 12 of your W-2 (that is the spread your employer already added to wages) and any broker supplemental statement. Verifying this one line is often worth tens of thousands of dollars.

The decision levers that actually move your bill

The spread is taxed as ordinary income no matter what — that part is fixed once you exercise. But three levers change the total:

1. Hold one year past exercise. This is the big one. It converts all post-exercise appreciation from ordinary rates (up to 37%) to long-term rates (0/15/20%). On Priya’s numbers that is a ~$40,000 swing. The risk you accept is concentration — you are betting the stock holds value for that year.
2. Spread large exercises across tax years. A $400,000 spread exercised in one year stacks deep into the 35% bracket. Split across two years, more of it can fill the 32% band ($197,301–$250,525 single, 2026) before tipping into 35% — and you smooth the FICA and NIIT exposure too.
3. Exercise when the spread is small. Exercising early in your tenure, when FMV is near strike, minimizes the ordinary-income layer and starts the long-term clock sooner. The tradeoff is cash out of pocket for shares you cannot yet sell (especially private companies).

A fourth, situational lever: time a large exercise into a lower-income year — a sabbatical, a gap after a layoff, or a year you switch from W-2 to self-employment — so the spread fills lower brackets before hitting the 32%/35% steps.

Where the dollars land: the jargon decoded

State tax on the NSO spread

Most states tax the NSO spread as ordinary wage income and tax capital gains at the same rate as ordinary income (no preferential rate). Two practical notes:

• No-income-tax states (Texas, Florida, Washington, Nevada, and five others) impose $0 state tax on both the spread and the eventual gain — Priya pays only federal. Note Washington layers a 7% excise tax on long-term gains over $250K, but that does not reach wage-type spread income.
• High-tax states (California 13.3% top, New York 10.9%, Hawaii 11%) tax the spread as ordinary income in the year of exercise. If you earn the option in one state and exercise after moving, expect a sourcing fight — states often claim the portion of the spread attributable to work performed there.

The decision lever

The ordinary-income tax on your NSO spread is locked in the day you exercise — you cannot avoid the W-2 hit or the FICA. What you fully control is the second layer: hold the shares more than one year past exercise and the appreciation is taxed at 15% instead of up to 37%, and split a large exercise across tax years so the spread fills the 32% band before tipping into 35%. On a $200,000 spread with $200,000 of later appreciation, those two moves are worth about $40,000. Pull your grant date, your exercise-date FMV (or current 409A), and your projected sale year onto one page, and the holding-period decision answers itself.