RSUs and ESPP, in Plain English

What is a restricted stock unit?

A restricted stock unit, or RSU, is a promise from your employer to give you shares of company stock on a future date, once a condition is met, usually just staying employed for a set schedule. You don’t own anything yet at grant. You don’t pay anything for the shares. You simply wait for them to vest.

Vesting is the day the promise becomes real. The shares land in your account, and from that moment they’re yours to hold or sell like any other stock you own.

That single fact, that RSUs are taxed at vest and not at grant or at sale, is the one piece of the mechanics worth memorizing, because everything else follows from it.

What happens, tax-wise, when RSUs vest?

The full market value of the shares on vesting day counts as ordinary income, added to your W-2 exactly like a bonus. If 100 shares vest at $80 each, that’s $8,000 of taxable wages that year, regardless of whether you sell the shares or hold them for a decade.

Here’s the part that surprises people: employers don’t withhold at your actual tax rate. They withhold at a flat supplemental-wage rate, currently 22% on supplemental wages up to $1 million in the year, and 37% on any amount above that. If your marginal bracket is 32%, 35%, or 37%, that flat 22% withholding falls short by 10 to 15 percentage points on every dollar that vested, and a large vest can turn into an unexpectedly large bill the following April.

Once the shares are yours, they also establish a cost basis, the vest-day value. Sell them the same day and there’s typically little or no additional gain to report. Hold them, and any further movement in price becomes a separate capital gain or loss when you eventually sell, on top of the ordinary income tax already owed at vest.

What is an employee stock purchase plan?

An employee stock purchase plan, or ESPP, works differently. Instead of a grant, you elect to have a percentage of each paycheck set aside during an offering period, and at the end of it, that money buys company stock, typically at a discount (often up to 15% off) from the lower of the price at the start or end of the period.

That discount is close to a guaranteed return before the stock moves at all, which is why participating, even if you plan to sell immediately, is usually worth doing if your household cash flow allows it.

What is the ESPP tax tripwire?

How the sale is taxed depends entirely on when you sell, and the rule has two separate clocks that both have to run out:

• At least two years from the offering date, and
• At least one year from the purchase date.

Sell after both conditions are met, called a qualifying disposition, and only the original discount is taxed as ordinary income; the rest of your gain gets the generally lower long-term capital gains rate. Sell before either date passes, a disqualifying disposition, and the entire discount is taxed as ordinary income immediately, with the remaining gain or loss taxed at short- or long-term capital gains rates depending on how long you actually held the shares.

Neither choice is automatically wrong. Selling immediately locks in the discount and removes concentration risk right away. Waiting for a qualifying disposition can save real money in tax, but it also means holding company stock, and therefore company risk, for longer.

The concentration question underneath both

RSUs and ESPP shares both point at the same underlying question: how much of your net worth do you want tied to the company that also pays your salary? A single bad quarter can hit your paycheck, your bonus, and your portfolio all at once, which is a very different risk profile than owning that same company as one slice of a diversified account.

There’s no universally right answer, and it depends on your total financial picture, how concentrated you already are, what else you’re holding, and what you’re saving toward. What is worth avoiding is the version where you never decide on purpose, and years of vests simply accumulate into a position nobody chose deliberately.

Once equity compensation starts generating real cash, deciding what to do with the proceeds is its own question, and one the funding order and Roth vs. traditional guides both pick up from here.

Sources

• Internal Revenue Service, Publication 15 (Circular E), Employer’s Tax Guide. Flat supplemental-wage withholding rates for RSU vesting.
• Internal Revenue Service, Publication 525, Taxable and Nontaxable Income. Tax treatment of restricted stock and employee stock purchase plans, including qualifying and disqualifying dispositions.

RSU and ESPP withholding gaps are one of the most common tax leaks we see in a plan built around equity compensation. The Wealth Builder Tax Leak Audit walks through this and eleven other places tax may be quietly draining your plan, in about five minutes.