Missouri Stock Options Tax: 4.7% Ordinary Income Rate, 0% Capital Gains (Since 2025), and $0 ISO Qualifying Disposition Tax

Missouri quietly became one of the most favorable income-tax states for tech employees with stock options. In July 2025, Governor Kehoe signed H.B. 594, which enacted a 100% capital gains deduction for individuals — retroactive to January 1, 2025 — making Missouri the first state to fully eliminate state tax on all capital gains for individual filers.¹ For stock option holders, this changes the entire calculus: ISO qualifying dispositions, NQSO post-exercise appreciation, and QSBS gains all hit $0 Missouri state tax. Missouri also has no state alternative minimum tax, meaning ISO exercises produce no Missouri ordinary income and no Missouri AMT. The only Missouri state tax remaining on stock option income is the 4.7% ordinary income rate on NQSO exercise spreads (W-2 income at exercise) and disqualifying ISO disposition spreads.

There is one city-level complication: both Kansas City and St. Louis impose a 1% earnings tax on wages — which includes NQSO exercise spreads for employees who live or work in those cities.² ISO exercises still escape the city tax because they produce no W-2 income at exercise. For Cerner/Oracle Health engineers in Kansas City, World Wide Technology employees in St. Louis, and employees at Missouri's growing tech scene, understanding where that 1% applies — and where it doesn't — is the key planning distinction.

Missouri Income Tax Rates 2026

Missouri uses a graduated income tax with eight brackets, with the top rate of 4.7% applying to taxable income above approximately $9,200.³ That threshold is so low that virtually every tech employee with a meaningful salary will pay 4.7% on their marginal ordinary income — including NQSO exercise spreads, disqualifying ISO dispositions, and RSU vesting income. The lower brackets (ranging from 1.5% to 4%) apply only to the first ~$9,200 of Missouri taxable income, which is negligible relative to a $500K option exercise.

Missouri's standard deduction mirrors the federal standard deduction — $14,600 for single filers and $29,200 for married filing jointly for 2026.³ Missouri taxable income is calculated starting from federal adjusted gross income, adding back Missouri-specific modifications and subtracting Missouri deductions and the capital gains deduction. The effective rate on a $500K NQSO exercise for a senior tech employee is substantially 4.7%.

Compared to the major tech states, 4.7% is favorable: California tops out at 13.3%, Minnesota at 9.85%, New York at 9.65%, and even Illinois at 4.95% slightly exceeds Missouri. The states with no income tax (Texas, Florida, Nevada, Tennessee) still have $0 on ordinary income, but Missouri's 0% capital gains deduction substantially narrows that gap for ISO holders and post-exercise NQSO shareholders.

The 100% Capital Gains Deduction: Missouri H.B. 594 (Effective 2025)

This is the transformative change. Governor Kehoe signed H.B. 594 in July 2025. The law allows Missouri individual filers to deduct 100% of capital gains reported on their federal income tax return when calculating Missouri adjusted gross income.¹ The deduction applies to all capital gains — both short-term and long-term, from any asset class. The effective date is retroactive to January 1, 2025, meaning Missouri residents who realized capital gains in 2025 (including ISO qualifying dispositions, stock sales, and QSBS gains) owe $0 Missouri state tax on those gains.

Missouri DOR has confirmed this applies to capital gains from stocks, real estate, and cryptocurrency equally. There is no cap, no income phaseout, and no distinction between short-term and long-term holding periods — all capital gains qualify for the 100% deduction.¹

ISO Treatment in Missouri

At exercise: $0 Missouri state tax

Missouri individual income tax begins with federal adjusted gross income (Missouri RSMo §143.121).⁴ Because an ISO exercise creates no W-2 income and does not affect federal AGI (it creates only a federal AMT preference item under IRC §56(b)(3)), there is no Missouri income at exercise either. Missouri has no state alternative minimum tax. The result: exercising ISOs produces $0 Missouri state income tax — regardless of the size of the exercise spread.

This stands in contrast to California (which taxes the ISO exercise spread as ordinary income under R&TC §17501 and also imposes a 7% state AMT) and Pennsylvania (which taxes ISO exercise spreads as ordinary income at exercise at 3.07%). Missouri follows the federal AMT-only treatment: the exercise is not a Missouri income event at all.

Qualifying dispositions: $0 Missouri state tax

A qualifying ISO disposition — selling shares held at least 2 years from grant date and 1 year from exercise date under IRC §422(a)(1) — produces a federal long-term capital gain. In Missouri, that gain is deducted 100% under H.B. 594. The result: $0 Missouri state tax on the qualifying ISO sale.

Combined with $0 at exercise, this means a Missouri resident who exercises ISOs and achieves a qualifying disposition owes no Missouri state tax at either step. The federal tax picture (20% LTCG + 3.8% NIIT above applicable thresholds) still applies, but the Missouri state tax is zero. This is the same outcome as Texas or Florida for ISO holders — even though Missouri nominally has a 4.7% income tax rate.

Disqualifying dispositions: 4.7% on the W-2 portion only

A disqualifying ISO disposition (selling before meeting the 2-year/1-year holding requirements) converts the exercise-date spread to W-2 ordinary income. That W-2 spread is subject to Missouri income tax at 4.7%. Any gain above the exercise-date FMV (post-exercise appreciation) remains capital gain — and is 0% Missouri state tax under H.B. 594.

NQSO Treatment in Missouri

Nonqualified stock option exercises generate W-2 ordinary income (the spread between strike price and FMV at exercise), subject to federal income tax, FICA, and Missouri state income tax at 4.7%.³ After exercise, any shares held and sold at a gain produce capital gain — taxed at 0% in Missouri under H.B. 594, regardless of how long the shares are held.

FICA does apply to NQSO exercise spreads. The Social Security wage base for 2026 is $184,500 — once your W-2 wages (including salary and any prior NQSO exercises in the same year) exceed that amount, additional NQSO exercise income faces only the 1.45% Medicare rate (plus 0.9% Additional Medicare Tax above $200K single / $250K MFJ).

QSBS in Missouri: Effectively $0 State Tax

Missouri applies no state tax to federally excluded QSBS gains via two independent mechanisms. First, Missouri begins individual income tax calculations with federal AGI — gains excluded from federal AGI under IRC §1202 are not included in Missouri taxable income.⁵ Second, even QSBS gains that are not excluded at the federal level (because they exceed the $15M cap, were issued before July 4, 2025 with lower exclusion percentages, or fall in the 28% taxable bracket) are capital gains — and Missouri's 100% capital gains deduction eliminates Missouri state tax on those as well.

The result: Missouri founders and early employees with QSBS stock options face $0 Missouri state tax on all QSBS-eligible gains. This is the same outcome as Texas, Florida, and Nevada — despite Missouri technically having an income tax.

Under the OBBBA §1202 rules (effective July 4, 2025): tiered exclusions of 50%/75%/100% at 3/4/5 years of holding, $15M gain cap (or 10× adjusted basis), $75M gross asset limit at issuance. Missouri's combined federal-AGI-starting-point mechanism and CG deduction make the entire QSBS structure tax-free at the state level for Missouri residents.

Kansas City and St. Louis: The 1% City Earnings Tax

Kansas City and St. Louis each impose a 1% city earnings tax on wages earned within the city.² This applies to all residents of those cities on their entire earned income, and to nonresidents on wages earned within city limits. The earnings tax is a tax on W-2 wages and self-employment income — not on investment income or capital gains.

Who pays the Kansas City or St. Louis earnings tax on stock option income:

• NQSO exercises: The exercise spread is W-2 income. Employees who work in Kansas City or St. Louis at the time of exercise owe 1% of the spread as city earnings tax. For a Kansas City-based Oracle Health engineer exercising $500K of NQSOs, that is $5,000 in city tax on top of the 4.7% Missouri state tax ($23,500). Combined city + state: $28,500 on $500K.
• RSU vesting: RSU vesting income is W-2 — same 1% city earnings tax applies if the employee works in KC or STL.
• ISO exercises: No W-2 income at exercise → no city earnings tax at ISO exercise. This is one of the few planning levers available: ISO exercises within Kansas City or St. Louis are entirely city-tax-free.
• Capital gains: Stock sales (qualifying dispositions, NQSO post-exercise appreciation, QSBS) are investment income, not "earnings" under the city earnings tax definitions — $0 city earnings tax.
• ESPP: The ordinary income component at vesting (W-2) is subject to the city earnings tax. Capital gain components are not.

If you work outside Kansas City or St. Louis city limits — at a Chesterfield campus, suburban Kansas City campus (e.g., Leawood, Overland Park, or Lee's Summit), or anywhere in Missouri outside these two cities — the earnings tax does not apply. The majority of Missouri geography is city-earnings-tax-free.

Kansas City's earnings tax requires employers to withhold from all wages earned within KC city limits, regardless of where the employee lives. If you live in Leawood, Kansas and work in Kansas City, Missouri, your NQSO exercise spread attributable to work in KC is subject to the 1% earnings tax. Conversely, if you live in Kansas City but work in a Kansas suburb, only your resident city earnings tax applies (1%) — not the nonresident rate (which is also 1%, so the practical rate is the same).

Missouri ISO vs. NQSO Tax Comparison (2026)

Nonresident Sourcing: Relocators and Remote Workers

Missouri uses the workday fraction to source stock option income for nonresidents: (days physically working in Missouri during the grant-to-exercise period) ÷ (total workdays during the grant-to-exercise period) × spread = Missouri-sourced income.⁶ This is the same basic methodology used by most states other than California and New York (which have additional complications).

The CA-to-MO relocator trap

If you accumulated stock option grants while working in California and then moved to Missouri, California may source a portion of the exercise income back to California using the California workday fraction. California is aggressive: it sources the income to California even after you've moved, based on the ratio of California workdays to total workdays during the grant-to-vesting (for options with a vesting period) or grant-to-exercise period. Missouri will credit Missouri residents for taxes paid to California on the same income under Missouri's resident credit provisions — so you generally pay the higher of the two states' rates on the California-sourced portion, not both rates stacked. But California's 13.3% top rate is so much higher than Missouri's 4.7% that the California-sourced fraction owed to California is typically larger than the Missouri credit. Work out your CA workday fraction before exercising large CA-era grants.

Remote workers with Missouri grants

A former Missouri employee who moved to California and exercises options from a Missouri employer would generally source the gain to Missouri using the workday fraction, not California. Unlike New York (which has the convenience-of-employer rule) and California (which will assert its own sourcing rules aggressively), Missouri uses a straightforward workday fraction based on physical presence. Missouri nonresident tax at 4.7% on the Missouri-sourced fraction, with potential credit against California tax paid.

Six Planning Strategies for Missouri Stock Option Holders

1. Prioritize ISO qualifying dispositions — they're free of Missouri tax start to finish

For Missouri residents holding ISOs, achieving a qualifying disposition (2-year/1-year holding) eliminates both the exercise-time Missouri tax (which was already $0) and the sale-time Missouri tax (0% via CG deduction). This is materially different from most income-tax states, where the qualifying disposition still produces state tax at the eventual sale. In Missouri, the qualifying hold produces the same $0 state tax result as if you were in Texas or Florida. Model your federal AMT exposure at exercise (use the ISO AMT Calculator) and coordinate with a fee-only advisor on the optimal tranche size to stay within your federal AMT safe zone — because the Missouri state tax picture makes the qualifying hold clearly dominant at the state level.

2. If you work in Kansas City or St. Louis, time NQSO exercises for lower-income years to reduce city and state taxes together

Both Kansas City and St. Louis impose a 1% earnings tax on wages. Missouri's 4.7% rate applies to the same W-2 spread. In lower-income years — sabbatical, parental leave, year-of-job-transition — your federal marginal rate is also lower, compressing the federal + state + city burden simultaneously. A year in which you reduce your salary income below the top federal bracket can save 7%–12% federal plus 5.7% Missouri + Kansas City combined, versus exercising in a peak-income year. Coordinate NQSO exercises with your tax advisor to identify the optimal timing window.

3. Use the capital gains deduction for post-IPO diversification — no state tax on any shares sold

Missouri employees who received shares at IPO (from ISO exercises, NQSO exercises, RSU vesting) and are now selling through a diversification program owe $0 Missouri state tax on all capital gains from those sales, regardless of how long they've held the shares. Unlike Illinois (4.95%), Minnesota (9.85%), or California (13.3%), Missouri allows full diversification of concentrated employer stock positions without any state tax friction. If you're managing a $2M–$10M concentrated position post-IPO and are a Missouri resident, this is a material tax benefit versus peer states.

4. Early exercise + 83(b) + QSBS: Missouri is clean for all three

Missouri startup founders and early employees at qualifying C-corps can stack the full §1202 QSBS benefit with early exercise and an 83(b) election. Missouri imposes no state tax on federally excluded QSBS gains, and Missouri imposes no state tax on any capital gains (excluded or not). For a $15M QSBS gain (100% excluded federally after 5+ years under OBBBA rules), Missouri state tax is $0. For a $2M QSBS gain partially excluded, Missouri still owes $0 — because even the non-excluded portion is a capital gain covered by H.B. 594. Missouri is one of the most QSBS-friendly states in the country, comparable to Texas, Florida, and Nevada.

5. For disqualifying ISO dispositions, model the 4.7% Missouri cost explicitly before deciding to sell early

Some ISO holders find that a disqualifying disposition is optimal at the federal level: it converts the AMT preference item to regular W-2 income, recovers the federal AMT credit, and sometimes reduces total federal tax versus holding for a qualifying sale. In Missouri, a disqualifying disposition also generates 4.7% state tax (and 1% city tax for KC/STL workers) on the W-2 component — which was $0 on the qualifying hold path. Run the full state + federal comparison before making this decision. For large exercises where the qualifying hold produces $0 Missouri tax versus a disqualifying disposition producing 4.7% + possibly 1% city, the Missouri state tax savings from the qualifying hold can be $25,000+ on a $500K exercise.

6. If you're considering relocating to Missouri from a high-tax state, calculate your grant-era sourcing fraction first

Moving from California, New York, Oregon, or Minnesota to Missouri is tax-favorable going forward — but prior-state grants may retain a sourcing fraction to your old state. California will source the portion of your option spread corresponding to your California workdays during the grant period, regardless of where you live at exercise. Run the workday fraction calculation for your largest outstanding grants: (CA workdays ÷ total workdays from grant date to today). If you have California-era grants with a CA fraction above ~40%, moving to Missouri reduces your going-forward tax burden but doesn't eliminate the California tail. Delay the CA-fraction exercises as long as practical post-move to let the CA fraction shrink with each additional workday logged in Missouri.

1. Missouri H.B. 594 — 100% individual capital gains deduction, effective January 1, 2025. Governor Mike Kehoe signed H.B. 594 in July 2025. The law allows individual Missouri income tax filers to deduct 100% of capital gains reported for federal income tax purposes when calculating Missouri adjusted gross income. The deduction applies to all capital gains — short-term and long-term, from all asset classes including stocks, real estate, and cryptocurrency. The effective date is retroactive to January 1, 2025. Missouri became the first state to fully eliminate capital gains tax for individual filers. Sources: Missouri Department of Revenue — Missouri: First State to Fully Exempt Capital Gains Tax; RubinBrown — Missouri Eliminates Tax on Capital Gains for Individuals; RSM US — Missouri Eliminates Capital Gains Tax (2025).
2. Kansas City and St. Louis city earnings taxes. Kansas City imposes a 1% earnings tax on all wages earned within the city limits, applicable to both residents and nonresidents who work in Kansas City (Kansas City Code §68-390). St. Louis imposes a 1% earnings tax on wages earned within the city (City of St. Louis Revenue Division). The earnings tax applies to W-2 wages including NQSO exercise spreads and RSU vesting income. Capital gains (including ISO qualifying dispositions, stock sale appreciation, and ESPP gain components) are not "wages" and are not subject to the city earnings tax. ISO exercises produce no W-2 income and are therefore not subject to the city earnings tax. Sources: City of Kansas City — Earnings Tax (kcmo.gov); City of St. Louis — Earnings Tax Information.
3. Missouri individual income tax rates and brackets, 2026. Missouri uses a graduated income tax with a top rate of 4.7% applying to taxable income above approximately $9,200. The Missouri standard deduction mirrors the federal standard deduction ($14,600 single / $29,200 MFJ for 2026). Missouri taxable income is calculated starting from federal AGI. The 4.7% top rate is the applicable rate for all practical NQSO exercise income and ordinary income from disqualifying ISO dispositions for tech employees with significant option grants. Sources: Missouri Department of Revenue — 2026 Missouri Withholding Tax Formula (dor.mo.gov); Tax Foundation — 2026 Missouri Tax Rates & Rankings.
4. Missouri income tax conformity to federal AGI; no Missouri state AMT. Missouri individual income tax is calculated beginning with federal adjusted gross income under RSMo §143.121. Because ISO exercise spreads create no W-2 income and do not affect federal AGI (the ISO spread creates only a federal AMT preference item under IRC §56(b)(3)), there is no Missouri income tax at ISO exercise. Missouri does not impose a state alternative minimum tax. Sources: Missouri DOR — Individual Income Tax (dor.mo.gov); Tax Foundation — Missouri 2026 State Tax Profile.
5. Missouri QSBS §1202 conformity and capital gains deduction. Missouri conforms to the federal §1202 QSBS exclusion because Missouri begins individual income tax calculation from federal AGI — gains excluded from federal AGI are not included in Missouri taxable income. Additionally, Missouri's H.B. 594 (100% CG deduction) eliminates Missouri state tax on any capital gain from stock sales regardless of federal treatment. Sources: Keystone Global Partners — 2026 QSBS by State: Eligibility Index; The Startup Law Blog — 2026 QSBS State Conformity Guide.
6. Missouri nonresident stock option sourcing — workday fraction method. Missouri sources stock option income for nonresidents using the workday fraction: Missouri workdays during the grant-to-exercise period divided by total workdays during the same period, multiplied by the option spread. This is the standard approach under Missouri's nonresident income tax rules. Missouri does not use California's aggressive workday-sourcing claims on former residents who have fully relocated; Missouri sources only the fraction attributable to Missouri work. California, however, will independently source Missouri residents' California-era option grants using California's own workday fraction. Sources: Missouri DOR — Individual Income Tax; Financial Planning Association — State Income Taxation of Nonresident Equity-Based Compensation.

Values verified June 2026. Missouri 4.7% top rate from MO DOR 2026 Withholding Formula (dor.mo.gov). H.B. 594 capital gains deduction effective January 1, 2025, per MO DOR and multiple practitioner sources (RubinBrown, RSM, Wipfli). Kansas City and St. Louis 1% earnings tax from respective city revenue division publications. Missouri has no state AMT. ISO treatment (no MO income at exercise) per MO RSMo §143.121 federal-AGI starting point. Nonresident sourcing uses workday fraction. Confirm current-year values with a Missouri-licensed tax advisor before making irreversible decisions.