Taxes When You Exercise Stock Options. The $200,000 Gain You Did Not Make.

A software engineer at a public company holds 10,000 nonqualified stock options with a $6 strike price. The stock trades at $26 and the grant expires in the spring, so one morning in November they exercise all of it and sell the shares the same day. Taxes when you exercise stock options arrive in two pieces, and the second piece is where the money gets lost. The November pay stub reports $200,000 of wages that never hit the bank account, and in February a Form 1099-B claims a $200,000 capital gain on a sale that made nothing. Both documents are correct. Filing the second one the way it prints costs $77,600.

Nothing is taxed at grant. Under Treas. Reg. §1.83-7, a nonqualified option with no readily ascertainable fair market value, which is essentially every employee grant because the option itself is not publicly traded, produces no income at grant or at vesting. The tax arrives the day you exercise, and IRC §83(a) sets the amount: the fair market value of the stock you received minus what you paid for it. Ten thousand shares at a $6 strike with the stock at $26 is $200,000, and it's compensation, not investment income. Your employer reports it in box 1 of the W-2, in box 3 up to the 2026 Social Security wage base of $184,500 and box 5 for Medicare, then separately in box 12 with code V so the IRS can see how much of your pay came from an option exercise. If part of a grant you thought was an ISO shows up there too, the $100,000 ISO limit is usually why.

Payroll treats the spread as supplemental wages (the category that covers bonuses, commissions, and equity income), so Publication 15 for 2026 withholds a flat 22%, rising to a mandatory 37% on supplemental wages above $1,000,000 for the year. The 22% is a withholding convention, not a tax rate. Stack $200,000 of spread on a $190,000 salary and the federal income tax on those dollars is $65,300 against $44,000 withheld. The $21,300 difference is yours to cover, which is the same gap behind owing taxes on RSUs that were already withheld. If the exercise lands in the fourth quarter, that money is due with the January 15, 2027 estimate rather than in April, unless your withholding already clears a safe harbor.

Publication 525 states the basis rule in one line: your basis in the shares is what you paid for them plus any amount you included in income on exercise. A $6 strike plus $20 of spread is $26, which is exactly what the shares were worth that morning, so a same-day sale produces a gain of about zero. Your broker will not report it that way. For stock acquired from a compensatory option granted or acquired on or after January 1, 2014, Treas. Reg. §1.6045-1 bars the broker from increasing initial basis by the compensation income you recognized. Box 1e gets $60,000, the strike price and nothing else. The broker is following the rule, not making a mistake: Treasury wrote it that way so employees would not have to guess whether a given broker had adjusted basis.

Accept that 1099-B as imported and your return shows a $200,000 short-term capital gain stacked on top of $200,000 of wages. The same dollars get taxed twice. At the 35% bracket plus the 3.8% net investment income tax under IRC §1411, the phantom gain costs $77,600 on a trade that made nothing.

The correction takes one line. Shares from options granted after 2013 are covered securities (the ones whose basis a broker has to report to the IRS), so the sale lands in box A of Form 8949 if you held the shares a year or less, box D if longer. The instructions for those boxes are specific: leave the broker's wrong basis in column (e), enter code B in column (f), and put the correction in column (g) as a negative number. On the numbers above, column (g) reads $200,000 as a negative and the reported gain drops to zero.

1. 01Pull the code V amount from box 12 of the W-2 for the year you exercised and divide it by the number of option shares. That is the spread per share. Add the strike price and you have your correct basis per share.
2. 02Compare it to box 1e of the 1099-B. If box 1e shows only the strike price times the shares, the sale needs the code B adjustment. If the transaction landed in box B or box E instead, meaning the broker did not report basis to the IRS, there is nothing to adjust: enter the correct basis in column (e) and -0- in column (g).
3. 03If you already filed a return with the uncorrected basis, the money is recoverable on Form 1040-X. IRC §6511 gives you three years from the date you filed or two years from the date you paid, whichever is later.

ESPP shares have the identical problem with different arithmetic, worked through in the ESPP cost basis post. Software does ask whether the imported basis is right. Most people click past the question.

The decision worth making is not how to report the trade, it's whether you are selling at all. On a same-day exercise the tax is unpleasant but the cash to pay it is sitting right there. Exercise and hold and you've written a $60,000 check for the strike and owe $65,300 of income tax on a gain that exists only on paper. If the stock halves before you sell, you get a capital loss usable against $3,000 of ordinary income a year, against a wage bill you already paid in full. Publication 550 gives holding its one real payoff: the clock starts the day after you exercise, and after more than a year the appreciation above $26 is taxed at 15% or 20% instead of your wage rate. That break reaches only what the stock does from here. The $200,000 spread is wages permanently, whatever happens next.