RSU Tax Guide 2026: Vesting, Withholding, and Sell Timing

Restricted Stock Units (RSUs) are the most common equity compensation vehicle at large tech companies — Google, Meta, Apple, Amazon, Microsoft, Netflix, and virtually every public tech employer. They're conceptually simple: your employer promises to give you shares of company stock on a future vesting date. When those shares vest, they become yours to keep or sell. The tax mechanics are where things get expensive. RSUs are taxed twice — once as ordinary wage income at vest, then again as capital gains when you eventually sell — and the withholding your employer applies is almost always insufficient for high earners, leaving them with unexpected tax bills at filing time.

The tax at vest is straightforward but severe. On the vesting date, the fair market value (FMV) of the shares — measured by closing price that day — is added to your W-2 wages. If 500 RSUs vest when the stock trades at $200, that's $100,000 added to your ordinary income for that year. This income is subject to federal income tax at your marginal bracket, state income tax (in most states), Social Security tax up to the wage base ($184,500 in 2026), Medicare tax at 1.45%, and Additional Medicare Tax at 0.9% on income above $200,000 (single) or $250,000 (MFJ) under IRC §1401. The full RSU value shows on your W-2 Box 1 as if it were paid in cash.

Employer withholding uses the IRS supplemental wage flat rate: 22% federal on RSU value up to $1 million per employee per year, then 37% on any amount above $1 million (IRS Circular E). Most companies withhold shares to cover this — 'sell-to-cover' — meaning they sell enough of your vested shares on the vesting date to pay the 22% federal withholding plus FICA. The remaining shares hit your brokerage account. For a $100,000 vest at 22% federal + 7.65% FICA, the company sells about 30% of shares to cover, leaving you with 350 shares from the original 500 vest. This process happens automatically at Fidelity, Schwab, ETRADE, or whichever brokerage your company uses.

The withholding gap is the biggest surprise for RSU-heavy compensation. A tech worker in the 32% federal bracket receiving $200,000 of RSU vests has $44,000 owed in federal income tax on those RSUs alone — but only $44,000 × (22/32) = $30,250 was withheld. The $13,750 shortfall becomes owed at tax filing time. On a $500,000 annual RSU vesting schedule (common for mid-level engineers at Big Tech), the shortfall can exceed $50,000. This is why so many tech workers get shocked April tax bills. The solution: increase your W-4 withholding through Step 4(c) 'Extra Withholding' by an amount that covers the RSU withholding gap divided over pay periods.

State supplemental withholding varies dramatically. California withholds RSU vests at 10.23% state supplemental rate. New York at 11.7%. Massachusetts at 5%. New Jersey at 11.8%. Texas, Florida, and other no-tax states withhold nothing. This state supplemental rate is often much higher than your actual marginal state rate — so on RSUs, high-earner California residents typically get some state tax refund since 10.23% withholding exceeds their 9.3% marginal state bracket. The reverse is true in some lower-tax states.

Real example: mid-level Google engineer, single, California resident, 2026. Base salary: $220,000. Annual RSU vest: $250,000. Total W-2 wages: $470,000. Federal income tax at 35% marginal on RSUs: $87,500 owed. Federal withholding on RSU: 22% × $250,000 = $55,000. Federal shortfall on RSUs alone: $32,500. Plus Additional Medicare Tax 0.9% × ($470,000 - $200,000) = $2,430. California state on RSU: 9.3% marginal × $250,000 = $23,250 owed vs 10.23% × $250,000 = $25,575 withheld — small state refund of $2,325. Net additional federal tax owed at filing: about $30,000 that wasn't withheld. Solution: adjust W-4 Step 4(c) to add roughly $1,200 per biweekly paycheck (26 pay periods × $1,200 = $31,200).

Post-vest capital gains treatment. Once vested, RSU shares become like any other stock you own. Your cost basis is the FMV on the vesting date (already taxed as ordinary income). Subsequent price appreciation is capital gain when you sell. Hold more than 1 year from vest date: long-term capital gain at 0/15/20% federal rates. Hold 1 year or less: short-term capital gain at ordinary income rates. The 1-year clock starts on the vest date, NOT the grant date. This is different from ISO holding period rules and trips up employees who confuse the two equity types.

The default 'sell everything at vest' strategy has strong tax logic. Reason: if you continue holding vested RSUs, you're effectively buying more of your employer's stock with money you already paid ordinary income tax on. That's the same as receiving cash comp and immediately investing it all in your employer — a highly concentrated position no diversified investor would voluntarily construct. Selling immediately at vest converts the ordinary-income-taxed asset to cash you can diversify. The tax cost is zero — you've already paid ordinary income tax on the vest value, and there's no additional gain (or minimal gain if stock moved between vest and same-day sale).

The 'sell to save on taxes' hold strategy is a common mistake. Some employees hold RSUs planning to convert ordinary income into long-term capital gains. But you've ALREADY paid ordinary income tax on the vest value. Holding just exposes future gains to 15-20% LTCG instead of ordinary rates. If the stock drops during your holding period, you have a capital loss on already-taxed money — a net loss compared to selling immediately. Holding RSUs is only justified if you affirmatively want employer stock exposure exceeding the value already invested via vested unsold shares.

Blackout windows constrain when you can sell. Public company employees are subject to trading blackout periods around earnings announcements — typically 2-4 weeks before and 1-2 business days after each quarterly earnings. Some companies impose broader blackouts around other material events (M&A negotiations, restatements). These blackouts can force you to hold RSUs through significant price moves you'd rather exit. Executives and directors with material non-public information have additional restrictions. Consider a 10b5-1 plan — a pre-scheduled trading plan filed with the SEC that lets you sell shares according to a predetermined schedule regardless of blackouts.

10b5-1 plans are the professional solution. Adopted under SEC Rule 10b5-1, these pre-scheduled selling plans specify: (a) prices you'll sell at, (b) dates you'll sell on, or (c) formulas that determine both. Once adopted, sales proceed automatically according to the plan regardless of blackout status. New SEC rules effective 2023 require a 90-120 day cooling-off period between plan adoption and first trade, and executives must certify they're not in possession of material non-public information at adoption. Most large employers coordinate with brokerages (E*TRADE, Schwab, Fidelity) that offer standard 10b5-1 plan templates.

IRMAA and tax cliff exposure for high-earning tech workers. In 2026, Modified Adjusted Gross Income above $200,000 single triggers the 3.8% Net Investment Income Tax on investment gains (dividends, capital gains, interest), plus the 0.9% Additional Medicare Tax on wages. Above $250,000 (single) MAGI, further AMT considerations may apply. IRMAA Medicare surcharges begin at $212,000 (married) in 2026, though this only affects retirees on Medicare. RSU vests routinely push tech workers into all these tiers — plan accordingly using the Tax Cliff Map to see where every threshold sits relative to your total comp.

State-migration tax planning for RSU. If you move states between grant and vest, both the origin and destination state may claim tax on the vest value. Most states apportion RSU income based on where you worked during the vesting period (grant date to vest date). California is particularly aggressive — a 4-year vesting cliff granted in California but vested after you moved to Texas still incurs California tax on the California-worked portion. Track your residency dates carefully and file part-year returns in both states. High-value RSU vests are frequently timed with cross-state moves to optimize state tax burden.

International RSU complications. Non-US citizens working in the US on H-1B or other visas face standard US RSU tax treatment. US citizens working abroad may face host-country tax on RSUs, with US foreign tax credit under IRC §901 available to offset double taxation. RSUs vested in the US while employed abroad may require Form 5471 or Form 8858 filings for informational purposes. Cross-border RSU tax is highly specialized — engage a CPA with international expertise if RSU vests exceed $50,000 in years with cross-border employment.

The double-tax myth. Some workers believe RSUs are 'double-taxed' because they're taxed at vest and again on sale. That's a misunderstanding. At vest: you're taxed on the value transferred to you (ordinary income). On sale: you're taxed only on the CHANGE in value since vest (capital gain or loss). The cost basis of $200/share at vest becomes the reference point — sell at $250 later and you owe LTCG on the $50 increment, not on the full $250. Selling at $150 later creates a $50 capital loss that offsets other capital gains or up to $3,000 of ordinary income annually.

Refresh grants complicate the picture. Most tech employers grant additional RSUs annually ('refresh grants') on top of the initial grant. Over a career, you accumulate multiple vesting schedules overlapping in complex ways. A senior engineer might vest 4 grants simultaneously — original 4-year grant vesting at years 1-4, first refresh year-2 grant vesting at years 2-5, second refresh year-3 grant vesting at years 3-6, etc. Total annual vest value can exceed base salary. Use a spreadsheet or a tool like Carta or Compound to track total expected vest by year for tax planning purposes.

Use the RSU Tax Calculator on this site to model your specific 2026 vest. Inputs: shares vesting, current stock price, state of residence, other annual income, filing status. The calculator computes: federal income tax owed on the vest value at your true marginal rate (not the 22% supplemental), state income tax, FICA including Additional Medicare, expected withholding shortfall, and the amount to add to your W-4 Step 4(c) to close the gap. Combined with the Total Comp Calculator, you can see the true after-tax value of your entire compensation package before making job-change or negotiation decisions.

Run this analysis on your actual salary.