Under Section 423 tax rules, an employee stock purchase plan lets you buy company stock at up to a 15% discount through after-tax payroll deductions, and you owe no income tax until you sell the shares. When you do sell, how long you held the stock decides whether most of your profit is taxed at long-term capital gains rates or at your ordinary income rate. The gap between those two outcomes on the same sale can be thousands of dollars.
Two numbers set the outer edges of the benefit. The purchase price has to be at least 85% of the stock’s fair market value, which is where the familiar 15% discount comes from. And no employee can accrue the right to buy more than $25,000 of stock per calendar year, measured at the undiscounted grant-date price rather than what you actually pay.1Office of the Law Revision Counsel. 26 USC 423 – Employee Stock Purchase Plans Because the cap uses the undiscounted price, the shares you actually receive can be worth more than $25,000 on the day you buy them. Most employers also impose a payroll-deduction cap of 10% to 15% of base salary; your effective limit is whichever ceiling binds first.
Nothing Is Taxed at Purchase
The defining feature of a Section 423 plan is that the discount is not taxed when the shares hit your account. You funded the purchase with after-tax dollars from your paycheck, and the bargain element — the gap between the stock’s fair market value and the price you paid — stays off your W-2 for the year of purchase.2Internal Revenue Service. Stocks (Options, Splits, Traders) 5 The full value of the discount stays invested in the stock until you decide to sell.
Your employer will send you Form 3922 by January 31 of the year after each purchase.3Internal Revenue Service. About Form 3922 – Transfer of Stock Acquired Through an Employee Stock Purchase Plan Under Section 423(c) It records the grant date, the purchase date, the fair market value on each of those dates, the price you paid, and the number of shares you got. You don’t file it with your return. File it in the folder you keep for the shares, because you’ll need those numbers to compute your tax when you eventually sell — potentially years from now.
One boundary worth naming: if your company’s plan doesn’t actually qualify under Section 423 (for example, it offers a discount deeper than 15% or carves participation down to a select group), the discount is taxed as ordinary income the day you buy. The rules below only describe qualified plans.
Qualifying Disposition: Hold Long Enough and Most of the Gain Is Capital
A sale is a qualifying disposition when you’ve held the shares for both of these periods: at least two years from the grant date (the first day of the offering period), and at least one year from the purchase date.1Office of the Law Revision Counsel. 26 USC 423 – Employee Stock Purchase Plans Both have to be satisfied. For a six-month offering period, the two-year-from-grant rule is almost always the binding one.
When you clear both holding periods, the amount reported as ordinary income is the lesser of two things: your actual gain on the sale, or the discount built into the option on the grant date (grant-date fair market value minus the option price).2Internal Revenue Service. Stocks (Options, Splits, Traders) 5 Everything above that is long-term capital gain.
Here’s how it plays out. The stock was $10 on the grant date. Your plan offers a 15% discount with a lookback (the price is 85% of the lower of grant-date or purchase-date value). By the purchase date, the stock had climbed to $15, so you bought at $8.50. Two and a half years later, you sell at $20. Ordinary income is $1.50 per share — the original 15% discount off the $10 grant-date price. The remaining $10 per share flows through as long-term capital gain. The lookback feature generated an additional $5.50 of embedded value at purchase, and in a qualifying disposition all of that upside is taxed at capital gains rates.
Disqualifying Disposition: Sell Early and the Full Purchase-Date Spread Is Wages
Sell before you’ve met either holding period and the math shifts hard against you. The ordinary income component is no longer capped at the grant-date discount. It becomes the full spread between the stock’s fair market value on the purchase date and what you actually paid.2Internal Revenue Service. Stocks (Options, Splits, Traders) 5 With a lookback, that spread can be much larger than the grant-date discount.
Using the same numbers: $10 at grant, $15 on the purchase date, $8.50 purchase price, $20 sale price. In a disqualifying disposition the ordinary income is $6.50 per share — the $15 purchase-date value minus the $8.50 you paid. The remaining $5 is capital gain, short-term if you held under a year after purchase and long-term if you held longer. Compare that to the qualifying result above where only $1.50 was ordinary income. The early sale converted $5 per share from capital gains rates to ordinary income rates.
Your employer reports the ordinary income from a disqualifying disposition on your W-2 for the year of the sale. The statute specifically says income tax withholding is not required on that amount.4Office of the Law Revision Counsel. 26 USC 421 – General Rules That matters at tax time: the income appears on your W-2 without any federal income tax having been pulled from your paycheck to cover it, so you can owe a larger balance than you expect. FICA (Social Security and Medicare) can still apply to that ordinary income if you’re still working for the company when you sell.
Selling at a Loss
If the stock has fallen below what you paid and you sell in a qualifying disposition, there’s no ordinary income — you can’t have negative ordinary income. You report a capital loss equal to sale price minus purchase price. That loss offsets other capital gains or up to $3,000 of ordinary income per year, with any excess carrying forward.
A disqualifying disposition at a loss is less forgiving. The ordinary income is still the spread between the purchase-date fair market value and your discounted price, because that spread existed the moment you bought the shares, regardless of what happened afterward. You then claim a capital loss for the decline from purchase-date value to sale price. The combined effect can sting: you owe wage tax on a discount even though the position lost money.
Watch the Wash Sale Window
Sell ESPP shares at a loss and the IRS treats any “substantially identical” stock you acquire within 30 days before or after the sale as replacement shares that disallow the loss.5Office of the Law Revision Counsel. 26 USC 1091 – Loss From Wash Sales of Stock or Securities An automatic ESPP purchase inside that 60-day window counts. The disallowed loss isn’t lost forever; it adds to the basis of the replacement shares, and you recover it when you sell those. But it can wreck your tax plan for the current year. The rule reaches across all your accounts, including your spouse’s. Before selling at a loss, look at the calendar and see when the next ESPP purchase date falls.
Reporting the Sale Without Paying Tax Twice
This is where ESPP participants most commonly overpay. Your broker reports the sale on Form 1099-B. The cost basis in Box 1e typically reflects only what you paid for the shares. It does not include the ordinary income already reported on your W-2. Copy those numbers straight onto your return and you’ll pay tax on the discount twice — once as wages, once as capital gain.
The fix is to add the ordinary income amount to your cost basis so your capital gain is calculated against the true economic basis. On Form 8949, enter the sale proceeds in column (d) and the broker-reported basis in column (e), then use column (g) to adjust for the ordinary income already in your wages.6Internal Revenue Service. Instructions for Form 8949 – Sales and Other Dispositions of Capital Assets The adjustment reduces the capital gain (or enlarges the capital loss) by exactly the amount you’ve already paid wage tax on. The totals move from Form 8949 to Schedule D and then to your Form 1040.
Form 3922 gives you the raw numbers you need: grant-date fair market value, purchase-date fair market value, and the price you paid. Keep it with your 1099-B when you sell.
If You Leave the Company — or Die Holding Shares
Quit, get laid off, or retire before the next purchase date and most plans refund your accumulated payroll deductions. There’s no tax consequence beyond what already applied to those after-tax dollars. Some plans will run one final purchase using your accumulated contributions; check your plan documents or ask your stock plan administrator before you give notice.
The statute requires that you remain employed from the grant date until at least three months before the purchase.1Office of the Law Revision Counsel. 26 USC 423 – Employee Stock Purchase Plans Leave earlier and you generally forfeit the right to buy for that offering.
Shares you already own stay yours. The qualifying and disqualifying rules keep applying when you sell, and the two-year and one-year clocks keep running whether you’re still employed or not.
If an employee dies holding ESPP shares, the holding period requirements don’t apply. The estate or the heir can sell without being forced into disqualifying treatment by the two-year and one-year thresholds.4Office of the Law Revision Counsel. 26 USC 421 – General Rules Any compensation income built into the shares may still be owed, but the favorable qualifying treatment applies automatically.