Are RSUs Taxed Twice? What's Actually Happening to Your Shares

No, RSUs are not taxed twice on the same dollar of value. They trigger two separate tax events over their life: ordinary income tax when they vest, and capital gains tax only on whatever the shares gain or lose after that. The real way people end up overpaying isn't a second tax on the same income, it's a reporting quirk on Form 1099-B that can make it look like you're being taxed on the full sale price instead of just the gain.

The Two Real Tax Events in an RSU's Life

Every RSU passes through, at most, two taxable moments: the day it vests and the day you eventually sell the resulting shares. Nothing is taxed before vesting, and nothing happens tax-wise if you simply hold vested shares without selling.

Ordinary Income at Vest

When RSUs vest, the full fair market value of the shares on that date counts as ordinary income, added to your W-2 wages for the year, exactly like a cash bonus would be. This happens whether or not you sell anything. If 100 shares vest at $50, that's $5,000 of taxable wage income, full stop.

Capital Gains (or Loss) at Sale

If you hold the shares after vesting and later sell them, you owe capital gains tax only on the difference between the sale price and the vest-date value, which becomes your cost basis. Sell the same day you vest and there's typically little or no additional gain to tax. Hold for a year or more after vesting and any gain qualifies for long-term capital gains rates instead of short-term, which are taxed as ordinary income.

Why This Isn't "Double Taxation" in the Technical Sense

Financial planning firm Facet points out that double taxation, properly defined, means a single source of income gets taxed twice. An RSU's vest-date value and its post-vest price appreciation are two different things, taxed once each. Facet's breakdown is blunt about this: RSUs can produce two tax bills, but that's two different income sources, not one income source billed twice.

Where the "Taxed Twice" Myth Actually Comes From

The myth persists because there's a real, specific mistake that makes it look true on paper, and it's common enough that several brokerages and tax-prep communities write about it every filing season.

Your 1099-B Often Shows a $0 Cost Basis

When you sell vested RSU shares, your broker issues a Form 1099-B reporting the sale. For shares received as compensation, brokers are often restricted from reporting your true cost basis, the vest-date value, in Box 1e, and instead print $0. If you file using that number as-is, you'd be taxed on the entire sale price as capital gain, even though you already paid ordinary income tax on the vest-date portion through your W-2.

Why Brokers Report It That Way

Brokerages frequently don't have visibility into what your employer already added to your W-2 at vest, so rather than guess, they default to $0 in the basis field and leave the correction to you or your tax preparer. It's a gap in the paperwork trail between payroll and the brokerage, not a second tax being assessed by the IRS.

The Fix: Form 8949 Adjustment Code B

The standard fix is a one-line adjustment on Form 8949 using code B, which corrects the basis to the vest-date value already taxed as wages, rather than accepting the broker's $0 figure. A walkthrough from Mezzi on this exact trap shows the adjustment turning what would have been an overstated six-figure gain into the much smaller real gain. Tax software can also apply this automatically, but only if you flag the sale as compensation-related stock rather than a plain brokerage sale, so check your Schedule D line after entering it.

The Real Way to Overpay: A Worked Example

The Vest

Say 200 shares vest at $125 each. That's $25,000 of ordinary income, included in your W-2 for the year, taxed at your regular rate alongside your salary.

The Sale

A year later you sell those 200 shares at $135, for $27,000. Your actual taxable gain is $2,000 ($27,000 minus the $25,000 basis), taxed at long-term capital gains rates since you held past a year.

What Happens If You Don't Correct the Basis

If your 1099-B shows $0 basis and you report it that way, you'd report the full $27,000 as gain instead of $2,000, effectively paying capital gains tax on money you already paid ordinary income tax on through your W-2. That's the overpayment people describe as being "taxed twice," and it's avoidable with the Form 8949 correction above.

Withholding at Vest Doesn't Cover Your Full Tax Bill

A separate, unrelated issue sometimes gets lumped into the "taxed twice" complaint: under-withholding at vest, which creates a second, larger-than-expected bill at filing, not a second tax.

The Flat 22% Supplemental Rate

Employers generally withhold a flat 22% federal rate on RSU income at vest, a supplemental-wage shortcut rather than your true marginal rate. Our deep dive on RSU withholding mechanics covers how that withholding actually gets collected, through sell-to-cover or net settlement, before shares ever reach your account.

Why This Creates a Second Surprise at Filing, Not a Second Tax

If your combined income puts you in the 24% bracket or higher, the flat 22% withheld at vest falls short, and you owe the difference when you file. That bill lands later, which makes it feel like a second, separate tax, but it's the same single ordinary-income tax on the vest-date value, just under-collected upfront.

Cross-Border RSUs: Where Genuine Double Taxation Can Happen

The one case where true double taxation is a real risk is working across two countries during the vesting period, where both jurisdictions can claim a right to tax the same vest-date income. This is a narrow, fact-specific scenario, governed by tax treaties and foreign tax credit rules that vary by country pair and by how long you worked in each location during the grant. If this applies to you, it's worth a cross-border tax specialist rather than general guidance, since the outcome depends entirely on your specific treaty and residency facts.

What to Check Before and After You Accept an Offer With RSUs

At Offer Stage

An offer letter's equity line rarely explains withholding or cost-basis mechanics, and it isn't supposed to. What matters at this stage is understanding the vesting schedule itself; our guide to how RSU vesting works and the vesting cliff explainer cover that groundwork before tax questions even come up. Offer XRay can flag when an offer's equity section is vague about grant size or schedule.

At Each Vest

Keep the vest confirmation your broker or stock plan provider sends for every vesting date. It shows the exact share count and fair market value used to calculate your W-2 income for that vest, which is the number you'll need later to correct your cost basis.

At Tax Time

Match each RSU sale on your 1099-B against your vest confirmations before filing. If Box 1e shows $0 or a number lower than the vest-date value, that's the signal to apply the basis adjustment rather than filing the broker's number as-is.

Frequently Asked Questions

Do I pay tax when RSUs vest even if I don't sell?

Yes. The fair market value of vested RSUs counts as ordinary income the moment they vest, regardless of whether you sell the shares immediately, hold them, or never sell at all.

Why does my 1099-B show a cost basis of $0?

Brokers are often unable to report your true cost basis for compensation-related stock, so they default to $0 in Box 1e. Your actual basis is the vest-date fair market value already included in your W-2; correcting it on Form 8949 avoids overstating your gain.

Is the 22% RSU withholding rate my actual tax rate?

No. It's a flat federal supplemental-wage withholding rate applied at vest, not your real marginal rate. If your income puts you above the 22% bracket, you'll likely owe more when you file, which can feel like a second tax but is the same single tax, just under-withheld.

Can RSUs really be taxed twice across countries?

In narrow cross-border cases, two countries can both claim tax on the same vest-date income, which is genuine double taxation. Tax treaties and foreign tax credits can sometimes offset this, but the outcome is specific to your residency facts and isn't something general guidance can resolve.

Key Takeaways

• RSUs create two distinct tax events, ordinary income at vest and capital gains at sale, not one tax charged twice on the same income.
• The real overpayment risk is a $0 cost basis on Form 1099-B; correct it with a Form 8949 adjustment (code B) using your vest-date value.
• The flat 22% withholding rate at vest often under-collects what you actually owe, creating a second bill at filing rather than a second tax.
• Genuine cross-border double taxation is possible but narrow, and depends on treaty and residency facts a general guide can't resolve.

The "taxed twice" worry usually traces back to a paperwork gap between your W-2 and your 1099-B, not an extra tax the IRS is actually charging. Reading your offer's equity terms closely before you sign is the easier half of this problem; if you want a second set of eyes on an RSU grant's structure before you accept, Offer XRay checks the equity section of an offer letter automatically.