The Second Set of Books: How do I avoid AMT on my stock options?

Every year, the IRS calculates your income tax twice.

The first calculation is the one you know: brackets, deductions, the refund or the bill. The second runs quietly in parallel, under different rules, with its own exemption and its own rates. It is called the alternative minimum tax, and the rule for reconciling the two is blunt: you pay whichever number is higher.

Most people never see the second calculation because the first one wins every year of their lives. Then they exercise incentive stock options, and the second set of books surfaces, with a bill attached.

What is the alternative minimum tax (AMT)?

The AMT was born in 1969, after the Treasury Secretary told Congress that 155 households earning over $200,000 had paid zero federal income tax. That year, Congress received more angry letters about those 155 families than about the Vietnam War. The fix was a parallel tax designed to ignore the deductions the wealthy were stacking.

Six decades later, the loopholes it targeted are mostly gone, and the system survives as a trap for a different crowd entirely: startup employees exercising stock options.

The second calculation starts with your income and strips out deductions the regular system allows. The standard deduction, gone. State and local taxes, gone. Then it adds income the regular system doesn't see at all, and the biggest item on that list is the ISO spread, the gap between what you pay for a share and what it is worth the day you exercise. The result is alternative minimum taxable income, or AMTI.

From AMTI you subtract an exemption — a band of income the AMT taxes at 0%: $90,100 for single filers in 2026, $140,200 married. It isn't a freebie everyone keeps: past $500,000 of AMTI, the band starts shrinking, and a large enough exercise erases it entirely.

Whatever survives is taxed at 26%, stepping up to 28% for the largest exercises.

That answer is your tentative minimum tax. Hold it next to your regular tax. The higher one is your bill.

Why do I owe tax if I never sold anything?

Jenny is a senior engineer holding 25,000 incentive stock options at a $2 strike, the price she is allowed to pay per share. Four years in, the company's latest 409A appraisal, the formal price tag on a private share, says each one is worth $22.

She exercises everything. Writes a $50,000 check, sells nothing, receives nothing. Nothing else about her year changes.

The regular calculation agrees that nothing happened. ISOs are the tax code's favored species of option, and exercising one creates no regular income at all. Her first set of books looks exactly like last year's.

The second set of books disagrees. It counts the spread — the $20 gap between her strike and the appraisal, on every one of her 25,000 shares — as income she earned the moment she exercised. Run her year through both calculations and they answer differently:

The rule is blunt: she pays the higher number. The difference between the two bottom lines — $197,000 against the $41,700 she was always going to owe — is a second check, for about $155,000.

That second check is exactly the alternative minimum tax: due in cash, on a gain that exists only on paper, attached to private shares she may not even be able to sell for years to come.

How much can I exercise before the AMT starts?

Jenny's mistake wasn't that she exercised — it was that she exercised all at once.

Every year there is a tax-free limit on how much spread you can recognize — the point where the AMT calculation finally overtakes the regular one. Your income sets it. Stay under and nothing happens. Go past it and only the excess is taxed, at about 26 cents on the dollar — not the whole exercise.

Jenny's limit is $30,500 of spread — at $20 a share, 1,525 shares, exercised for exactly $0 in extra tax. And it doesn't carry forward: whatever she leaves unused expires at midnight on December 31, and a fresh limit starts the next morning. A year she skips is a year thrown away.

What is my own limit?

The limit is different for everyone. It moves with filing status, salary, and the spread on your specific grant, so find yours before you exercise, not after.

What if my limit isn't enough?

December 31 and January 1 sit one day apart on the calendar, and a full tax year apart in the eyes of the AMT. The calculation is annual, and it resets at midnight on New Year's Eve. An exercise split across that boundary lands on two separate returns, each with its own fresh limit.

Timing decides how much that is worth. Rewind Jenny's company to the year its 409A read $4.44. At that price her entire grant carries $61,000 of spread — exactly two years' worth — and a single December order for all of it puts a full year's worth over the limit.

Now split the same order: 12,500 shares on December 31, 12,500 more on January 1. Each half lands on its own return, exactly at that year's limit. The AMT doesn't shrink. It disappears. The whole grant, exercised inside 24 hours, with nothing owed on either return.

Waiting has a price, but the boundary keeps helping. At today's $22 the grant is far too big for two years to absorb, yet the straddle still cuts the bill from $155,000 to about $119,600 — roughly $35,000 saved for signing the second order a day later.

Do I ever get the AMT back?

AMT paid on an ISO exercise is not money burned. It is closer to a forced prepayment.

The excess becomes a minimum tax credit that flows back in later years, whenever your regular tax is once again the higher number. Form 8801 keeps the ledger, and once the shares are finally sold, much of the timing washes out.

The dangerous word is later. The credit returns slowly, capped each year by the gap between your two calculations, and it only helps if there is a future to apply it against. In 2000, engineers exercised at the peak, watched their shares collapse, and still owed AMT on spreads that no longer existed, sometimes more than the shares were ever worth again. Congress passed relief for them eight years later. Waiting on Congress is not a plan.

So what should I actually do?

Exercise before the spread exists. The AMT taxes the gap between strike and value, so the cleanest strategy is the 83(b) election: exercise early while strike and value are nearly equal, file the one-page election within 30 days, and there is no spread for either set of books to see.

Already sitting on a spread? Exercise up to your limit. Take only as many shares as the limit covers, every single year, and remember the straddle: two years' worth always sit one midnight apart. A year you skip is a limit thrown away.

Exercise in January, decide in December. The AMT is an annual calculation, so an early-year exercise buys eleven months of information. If the stock craters, sell the exercised shares before December 31 and the AMT adjustment disappears, leaving ordinary tax on only the real gain. If it climbs, keep holding: a year past exercise (and two past grant), the sale qualifies for long-term capital gains.

The AMT is not a penalty for exercising. It is a penalty for exercising blind. The second set of books is public, the math is knowable in January, and the whole trap dissolves for anyone who checks their limit before writing the check.

Find your line, and fill it every year.