How to Report Stock Options on Your Tax Return

For tech employees who exercised ISOs or NQSOs, sold option shares, or participated in an ESPP in the prior tax year. Federal treatment; state reporting varies. Not tax advice — your specific facts control.

Documents you'll receive (and what each one does)

Before filing, collect every equity-related document from your employer and broker. Missing one causes cascading errors.

NQSO exercises: what shows up on your W-2

When you exercise a nonqualified stock option (NQSO), your employer treats the spread — (FMV at exercise) minus (strike price) — as ordinary compensation income in the exercise year. This amount appears in:

• W-2 Box 1 (Wages). The spread is added to your salary and all other compensation. It's already in the Box 1 total.
• W-2 Box 12, Code V. Many (not all) employers separately disclose the NQSO income here as an informational amount. It is NOT an additional amount — it's a subset of Box 1.
• FICA withheld (W-2 Boxes 4 and 6). Unless your total W-2 wages already exceeded the Social Security wage base ($184,500 in 2026)¹ before the exercise, the spread is subject to Social Security (6.2%) and Medicare (1.45% + 0.9% Additional Medicare Tax above $200,000 wages). Your employer withholds these at exercise.

The 1099-B cost basis problem for NQSO shares

This is the most common filing error for NQSO holders. Here's how it happens:

You exercised 5,000 NQSOs at a $10 strike when FMV was $50. The $40 spread × 5,000 shares = $200,000 appeared on your W-2 as ordinary income. You paid income tax on it. Your actual cost basis per share is $50 (strike + ordinary income = $10 + $40).

Later, you sell all 5,000 shares at $60. Your 1099-B may show:

• Uncovered / non-reported basis: $10 per share (strike only) — OR —
• Covered, unadjusted basis: $10 per share (if broker received only the exercise price)
• Covered, adjusted basis: $50 per share (correct — if your broker properly received the compensation adjustment)

If you use the $10 basis shown on the 1099-B without adjusting it, you report $250,000 in gain ($60 − $10 per share × 5,000). But $200,000 of that was already taxed as ordinary income on your W-2. You'd be paying tax on the same income twice. The correct gain is $50,000 ($60 − $50 × 5,000) — the post-exercise appreciation only.

How to fix the cost basis on Form 8949

When you complete Form 8949 (which flows to Schedule D):

1. Enter the proceeds from the 1099-B (Column D).
2. Enter the corrected cost basis in Column E (strike + W-2 ordinary income recognized).
3. In Column B (basis reported to IRS), enter "B" if broker reported incorrect basis, or "E" if broker didn't report basis.
4. In Column G (adjustments), enter the difference between the corrected basis and the reported basis as a negative number — this reduces your taxable gain to the correct amount.
5. In Column H, note the code: "B" for incorrect basis reporting by broker.

Most tax software (TurboTax, H&R Block, TaxAct) has a specific workflow for "employee stock" or "stock option" sales that walks through this adjustment. But you must know to use it — the default import from a 1099-B will populate the wrong basis.

ISO exercises: what you need to report (and when)

ISOs are more complex because the reporting obligations depend on whether you had a qualifying or disqualifying disposition.

In the year you exercise ISOs (no sale yet)

If you exercised ISOs and held the shares, you have no regular income tax event — but you may have an AMT event.

• Form 3921 (copy received from employer): Use this to calculate your ISO AMT preference item. The preference item is: (FMV at exercise date from Form 3921) minus (exercise price from Form 3921) × (number of shares exercised). This amount goes on Form 6251, Line 2i.²
• Form 6251 (Alternative Minimum Tax — Individuals): You must complete this if you exercised ISOs. The ISO spread is an "adjustment" that increases your Alternative Minimum Taxable Income (AMTI). If your tentative minimum tax exceeds your regular tax, you owe AMT.
• No W-2 impact: Unlike NQSOs, ISO exercises do not appear on your W-2 as wages. If your employer added the ISO spread to Box 1, that's an error (a surprisingly common one for companies without experienced stock plan admins).

Use the ISO Exercise AMT Calculator to model whether your exercise creates an AMT liability before you file. If you exercise a large tranche in December, you may need to make a Q4 estimated tax payment to avoid underpayment penalties — AMT is not withheld from paychecks.

In the year you sell ISO shares — qualifying disposition

A qualifying disposition requires: (1) sale ≥ 2 years after grant date AND (2) sale ≥ 1 year after exercise date. Both conditions must be met.

Tax treatment:

• No W-2 income. The entire gain — from strike price to sale price — is capital gain. If both holding period conditions are met, it's long-term capital gain taxed at 0/15/20% rates.⁴
• Cost basis on 1099-B: The broker typically shows the strike price as cost basis. For a qualifying disposition, your correct cost basis IS the strike price (you never recognized ordinary income), so the 1099-B is usually right. Verify against Form 3921.
• AMT adjustment: In the year of sale, you make a negative adjustment on Form 6251. The AMT basis of your shares was the FMV at exercise (because you recognized the spread as an AMT preference item in the exercise year). On a qualifying disposition, your regular-tax gain (measured from strike) is larger than your AMT gain (measured from FMV at exercise). The difference reduces your AMTI, which may reduce your AMT or generate an AMT credit recovery.
• Form 8801 (AMT credit): If you paid AMT in a prior year on ISO exercises, track the credit carryforward. A qualifying disposition can reduce your AMT and accelerate recovery. See the AMT Credit Carryforward Guide.

In the year you sell ISO shares — disqualifying disposition

A disqualifying disposition is any sale that fails either holding period requirement (e.g., same-day sale at exercise, or sale within 1 year of exercise).

Tax treatment:

• W-2 ordinary income: Your employer should add the lesser of (a) the spread at exercise or (b) the gain at sale to your W-2 wages in the year of sale. This shows up in Box 1. Many stock plan administrators handle this correctly; some miss it, which creates a mismatch with the IRS.
• Cost basis adjustment: Same problem as NQSOs. The 1099-B may show only the strike price as basis. Your actual basis = strike + ordinary income recognized (the W-2 amount). Adjust on Form 8949 as described above.
• No AMT preference item in sale year: Because you're recognizing ordinary income, the ISO AMT adjustment from the exercise year is reversed. You make a negative Form 6251 adjustment in the sale year.

ESPP shares: Form 3922 and the two-tax-event trap

Employee Stock Purchase Plan (ESPP) shares have two distinct tax events — the purchase date and the sale date — and most participants underreport because their 1099-B shows the wrong basis.

Qualifying ESPP disposition (held ≥ 1 year from purchase AND ≥ 2 years from offering date)

• The "compensation element" — the lesser of (a) discount from FMV at offering date or (b) actual gain — is ordinary income (W-2) in the year of sale.
• Any additional gain above the compensation element is long-term capital gain.
• Your employer should report the compensation element on your W-2 in the sale year. Verify this matches your Form 3922 math.

Disqualifying ESPP disposition (sold before the above holding periods)

• The entire discount at purchase date — (FMV at purchase) minus (your purchase price) — is ordinary income on your W-2 in the year of sale.
• Any additional appreciation above that is short-term or long-term capital gain depending on how long you held after purchase.

In both cases: your 1099-B often shows the purchase price as cost basis. Your correct basis = purchase price + ordinary income recognized (the W-2 component). Adjust on Form 8949.

Form 6251: AMT in depth

If you exercised any ISOs during the year, you must complete Form 6251. The key line is Line 2i: "Exercise of incentive stock options." Enter the ISO spread (FMV at exercise minus exercise price, per Form 3921) as a positive adjustment here.

After adding the ISO spread and other AMT adjustments to your regular taxable income, Form 6251 computes your Tentative Minimum Tax. If this exceeds your regular tax (from Form 1040), you owe the difference as AMT.

Key AMT interactions:

• State and local tax deduction (SALT). The $10,000 SALT cap doesn't exist for AMT — you add back any SALT deduction you took for regular tax purposes, which increases AMTI. Tech employees in CA or NY face significant SALT-driven AMT.
• Miscellaneous deductions. Several itemized deductions allowed for regular tax are disallowed for AMT, increasing AMTI.
• Phaseout of exemption. At 2026 AMTI above $500,000 (single), your $90,100 exemption phases out at $0.50 per dollar. At $680,200 AMTI single, the exemption is fully phased out and you're paying 26/28% on the full AMTI.

Tracking your AMT credit (Form 8801)

AMT paid on ISO exercises is not lost — it becomes an AMT credit (also called the minimum tax credit or MTC). In future years when your regular income tax exceeds your tentative minimum tax, you can apply the credit to reduce your regular tax dollar-for-dollar.

Form 8801 tracks this credit. The credit carryforward from prior years is on line 14 of last year's Form 8801 (or Form 8801 is embedded in your return summary). Each year, you can claim the excess of your prior-year credit against the current-year excess of regular tax over AMT.

Years with large deductions, lower income, or ISO qualifying-disposition sales are often the best years to recover the credit. A specialist can model optimal recovery windows across multiple years. See the AMT Credit Carryforward Guide for strategies.

Long-term capital gains rates: 2026 thresholds

For stock option shares sold after meeting the holding requirements, the applicable LTCG rate depends on your taxable income in the year of sale:⁴

Add 3.8% Net Investment Income Tax (NIIT) if your MAGI exceeds $200,000 (single) or $250,000 (MFJ) — these thresholds are NOT inflation-adjusted. For large qualifying ISO dispositions, the effective federal rate on long-term gain is 23.8% (20% + 3.8% NIIT).

Six common mistakes — and how to avoid them

1. Double-counting ordinary income via uncorrected 1099-B basis. As described above: if your broker reports strike price as basis and you don't add back the W-2 compensation element, you pay tax twice. Fix: use the Form 8949 adjustment column. In TurboTax, use the "Employee Stock" or "ESPP" import workflow that asks for the compensation amount from your W-2.
2. Forgetting to file Form 6251 after ISO exercise. If you exercised ISOs and held shares, AMT applies even if you didn't sell. Many employees skip Form 6251 because they didn't receive a 1099-B. The IRS will match Form 3921 data to your return; a missing Form 6251 triggers a correspondence audit.
3. Treating ISO exercise income as W-2 wages when it isn't. If you receive a W-2 with ISO spread in Box 1, contact your payroll department — this is typically an error for a qualifying-period hold. It inflates your W-2 wages and can cause FICA overwithholding and incorrect MAGI calculations.
4. Using AMT basis instead of regular basis on Form 8949. For a qualifying disposition sale, your regular-tax basis is the strike price (correct). Your AMT basis is the FMV at exercise (higher). Using the wrong basis for the wrong form understates regular-tax gain or creates an incorrect AMT adjustment.
5. Missing the ESPP compensation element in the sale year. ESPP participants sometimes forget that part of their gain is ordinary income when they sell, especially on a qualifying disposition where the W-2 hit comes years after the purchase. Check your W-2 Box 1 carefully in any year you sell ESPP shares.
6. Failing to make Q4 estimated tax payments after a large ISO exercise or NQSO exercise. Withholding on stock option events is often far below your marginal rate. If you exercised $500,000 worth of NQSOs in November at 22% withholding but owe 37% federal + 13.3% CA, the shortfall is substantial. The underpayment penalty applies even if you pay in full by April 15.

When a CPA or tax specialist is worth it

DIY software handles simple W-2 + 1099-B scenarios reasonably well. But if any of the following apply, the cost of an error or missed optimization significantly exceeds a professional fee:

• You exercised ISOs and held shares — AMT calculation is complex and software can miscalculate it
• You have multi-year ISO AMT credits and want to model recovery
• You had a disqualifying disposition — correct cost basis adjustment is easy to miss
• You moved states during or after the exercise year — state sourcing (CA, NY, PA) creates multi-state return complexity
• Your combined option income is $500K+ — the marginal cost of an error is high
• You have QSBS shares — the exclusion calculation and any state decoupling needs expert handling

A fee-only financial advisor who specializes in equity compensation can coordinate with your CPA or do a pre-filing review of your Form 6251 and Form 8949 entries — catching errors before they become penalties or audits. They can also model multi-year exercise strategies to minimize the total tax bill, not just the current year.