ESPP vs RSU: Key Differences Explained

Seen as RSU vs ESPP, the gap is simple: one is pay, and the other is a purchase. The table compares them on what each is, who pays, who uses it, the legal and tax treatment, the risk, when you can sell and a typical case.

An ESPP runs in offering periods. During each one, the company takes an after-tax amount from every paycheck. On the purchase date, it buys shares for you with the money. Under Section 423, the price can be as low as 85% of the share value on the first day of the offering or on the purchase date, whichever is lower. That feature is called a lookback.

You can buy no more than $25,000 of stock a year, valued at the start of each offering. Anyone owning 5% or more of the company cannot join. The shares are yours once bought, and your basis starts at the price you paid. If you withdraw before a purchase date, most plans return the money set aside. The ESPP guide covers enrollment and paystubs.

An RSU is a promise. Each unit usually equals one share, delivered when the unit vests, meaning when you have met its conditions. A common schedule is four years, with the first quarter vesting after one year. Until then, you own nothing. If you leave before a unit vests, you usually lose it.

At many private companies, units have two conditions. You must work long enough, and the company must have an IPO or a sale. This is called double-trigger vesting. Units can pile up for years without turning into shares, and with no tax due. The RSU guide covers how they vest.

Because an RSU is only a promise, it is not property under Section 83 of the tax code. So you cannot make an 83(b) election on it to be taxed early. Section 83 reaches the shares only when they are delivered to you.

RSU Taxes

When RSU shares are delivered, their value that day is wages. It appears on your Form W-2 with your salary. Your employer withholds federal income tax at 22%, the flat rate for supplemental wages, or 37% on supplemental wages above $1 million in the year. Social Security tax of 6.2% applies up to $184,500 of wages in 2026, and Medicare tax of 1.45% applies to all of it.

Withholding is usually paid in shares. The company keeps back some of them, or sells some for you, and sends the tax to the IRS. Your basis in the shares you keep is their value at delivery. If you later sell, the change from that value is a capital gain or loss. It is long term if you held the shares more than one year. The RSU taxes guide works through a full year.

ESPP Taxes

Buying ESPP shares is not taxed. The tax comes when you sell, and its shape depends on timing. A sale at least two years after the offering began and one year after purchase is a qualifying disposition. Your ordinary income is then the smaller of the discount at the start and your actual gain. The rest of the gain is long term.

An earlier sale is a disqualifying disposition. Your ordinary income is the full spread on the purchase date, even if it exceeds your gain. That amount is added to your basis, and the rest is a capital gain or loss. No income tax, Social Security or Medicare is withheld on ESPP income. The company reports your purchase to you on Form 3922.

The Same $10,000, Taxed Three Ways

An employee gets an RSU grant worth $10,000 at $20 a share, so 500 units. In the same year, she puts $10,000 into an ESPP whose offering starts at $20. The stock is $24 when the units vest and the ESPP buys. She sells everything at $30, more than a year later. In the third column, she sells the ESPP shares six months after the purchase.

The RSU is worth more because it cost her nothing: $15,000 of value against $7,644 of profit on the ESPP. But $12,000 of the RSU value is wages, taxed at her full rate with payroll tax. In the qualifying ESPP sale, only $1,764 is ordinary income, 23% of the profit, and the rest is long-term gain. Selling early pushes that share above half, to $4,116, and the rest becomes a short-term gain, taxed like wages.

Employee Stock Purchase Plan

For

A discount of up to 15%, sometimes on a lower past price. Shares are yours at once. A qualifying sale turns most of the profit into long-term gain.

Against

Uses your own pay. Nothing is withheld, so the tax comes at filing. Rare at private companies, where the shares are hard to sell.

Verdict: an ESPP suits an employee of a listed company who can spare part of each paycheck. The discount is the main return, and it arrives on the purchase date. Holding the shares afterward is a separate bet on the company that pays your salary.

Restricted Stock Units

For

No cash needed. Tax is withheld at delivery. The full value of each share is yours, minus tax.

Against

Taxed as wages at your full rate. Unvested units are lost if you leave. At private companies, units can wait years for an IPO or a sale.

Verdict: RSUs suit any employee, because they cost nothing to receive. Their drawback is the tax: the whole value at delivery is pay. The 22% withheld is often less than the tax due on a large delivery.

If you work at a public company with both, track two sets of dates. For RSUs, the delivery date sets your income and starts your holding period. For ESPP shares, the offering start and the purchase date decide which tax rule applies when you sell.

If you work at a private company, RSUs are the more common award, and they may not settle until an IPO or a sale. Units that have not settled usually cannot be sold in a tender offer. The tender offer taxes guide covers what selling there costs. For retirement plans that hold company stock, see ESOP vs ESPP, and for options, ISO vs NSO.

Common Mistakes

• Treating RSU withholding as the full taxThe 22% is a prepayment. If your top rate is higher, the rest is due when you file.
• Using the broker’s basisFor ESPP shares, the form often shows only the price you paid. Add the ordinary income from your W-2, or you pay tax on it twice.
• Selling ESPP shares a few weeks earlyMissing the two-year and one-year dates turns more of the profit into ordinary income.
• Expecting tax to be withheld on ESPP salesNothing is withheld. Set money aside, or make an estimated payment.
• Holding everything in one companySalary, RSUs and ESPP shares all depend on the same employer.

Employee stock purchase plan (ESPP)

A plan under Section 423 that lets employees buy company stock from their pay at up to a 15% discount.

Restricted stock unit (RSU)

A promise to deliver a share, or its cash value, once conditions are met. Taxed as wages on delivery.

Lookback

An ESPP feature that prices the purchase at the lower of the share value at the start and on the purchase date.

Vests

Meets its conditions. An RSU that vests turns into a share, or cash, and is taxed then.

Double-trigger vesting

RSU vesting that needs both enough time worked and a liquidity event, such as an IPO or a sale.

Supplemental wages

Pay outside regular salary, such as bonuses and RSU income. Federal income tax is withheld on it at a flat 22%.

Qualifying disposition

A sale of ESPP shares at least two years after the offering began and one year after purchase.

Disqualifying disposition

A sale of ESPP shares before those dates. The full spread on the purchase date becomes ordinary income.

Basis

What your shares cost for tax, including income already taxed on them. Your gain is the sale price minus your basis.

Every rule and figure was checked against the US Code and the IRS on October 29, 2026. They are US federal rules for tax year 2026. The worked example is illustrative arithmetic on those rules and uses no market data. Plan terms vary within these limits. State tax is not covered.