Exercise or Wait? A Guide to Startup Stock Option Decisions

You have stock options at your startup. They're vesting nicely. And now you face the question that keeps financially-minded startup employees up at night: should you exercise now, or wait? The answer isn't obvious, and the wrong decision can cost you tens of thousands of dollars in unnecessary taxes — or leave you holding worthless paper when you could have walked away clean.

This isn't a one-size-fits-all decision. It depends on the type of options you hold, your tax situation, your cash reserves, how much you believe in the company, and how close the company is to a liquidity event. Let's build a framework for thinking through it.

The Case for Early Exercise

Early exercise means buying your shares before you need to — sometimes even before they've fully vested (if your plan allows it). The primary reason to exercise early is taxes. With ISOs, exercising when the spread between your strike price and fair market value is small minimizes your AMT exposure. With NSOs, exercising when the spread is small minimizes your ordinary income tax hit.

Here's a concrete example. You have 10,000 ISOs with a $1 strike price. Today, the 409A value is $2. If you exercise now, the spread is $1 per share — $10,000 total. This $10,000 spread is an AMT adjustment (not regular income tax, but it factors into your AMT calculation). For most people, a $10,000 AMT adjustment is manageable and might not trigger any additional tax at all.

Now imagine you wait three years. The 409A is now $20. The spread is $19 per share — $190,000. That AMT adjustment could trigger a massive AMT bill, potentially $40,000-$60,000 in taxes on income you haven't actually realized. You're paying cash taxes on paper gains. This is the scenario that has caused real financial pain for startup employees, especially during periods where stock values later dropped.

Understanding AMT and ISOs

The Alternative Minimum Tax is a parallel tax system designed to ensure high earners can't avoid taxes through deductions and preferences. When you exercise ISOs, the spread is treated as an AMT "preference item." You calculate your taxes two ways — regular and AMT — and pay whichever is higher.

The AMT exemption for 2026 is roughly $85,000 for single filers and $133,000 for married filing jointly. If your AMT adjustments (including the ISO spread) stay below these thresholds after accounting for your regular tax, you may owe no additional AMT. This is why exercising early, when the spread is small, is so powerful — you can often stay under the exemption.

If you do trigger AMT, there's a silver lining: the AMT you pay generates an AMT credit that you can use to offset regular taxes in future years. It's not lost money — but it is money you've paid earlier than necessary, and recovering the credit can take years.

The 83(b) Election: Exercising Unvested Shares

Some option plans allow "early exercise" of unvested shares. You buy the shares before they vest, and any unvested shares are subject to a repurchase right — if you leave, the company buys back the unvested shares at your exercise price. The reason to do this is to file an 83(b) election with the IRS within 30 days of exercise.

The 83(b) election tells the IRS: "I want to be taxed on these shares right now, at their current value." If you early-exercise when the spread is zero (strike price equals fair market value) or very small, you owe little to no tax. Then, as the shares vest and appreciate, all the gain is taxed at capital gains rates — not as ordinary income. Without the 83(b), you'd owe ordinary income tax on each tranche as it vests at whatever the shares are worth at that time.

The 30-day deadline for filing the 83(b) is absolute. Miss it by one day and it's gone forever. This is one of the most commonly missed deadlines in startup equity, and it can cost tens or hundreds of thousands of dollars in additional taxes. If you early-exercise, file the 83(b) immediately. Mail it certified mail, keep copies, and follow up.

The Case for Waiting

Early exercise isn't always the right call. The biggest risk: you pay real money for shares that might become worthless. If you exercise 10,000 shares at $2 each, that's $20,000 in cash. If the company fails, that $20,000 is gone. Plus any taxes you paid on the spread.

Waiting makes sense when the exercise cost is high relative to your savings — don't put yourself in financial hardship to exercise options. It also makes sense when you're uncertain about the company's prospects, when the company is close to a liquidity event (IPO or acquisition) where you could exercise and sell simultaneously, or when you have NSOs where early exercise doesn't provide the same AMT advantage as ISOs.

With NSOs, the spread at exercise is always ordinary income, whether you exercise early or late. Exercising early locks in a smaller ordinary income hit, which is good — but you're also putting cash at risk. The tax savings need to justify the risk of losing your investment.

The 90-Day Clock: What Happens When You Leave

Here's where the exercise decision gets urgent. When you leave a company (voluntarily or not), you typically have 90 days to exercise your vested options. After that, unexercised options expire worthless. This 90-day window has forced countless startup employees into an impossible decision: come up with potentially tens of thousands of dollars in cash (plus a tax bill) within three months, or walk away from equity you've earned over years.

Some progressive companies have extended this window to 5, 7, or even 10 years for employees who've been at the company for a certain period. This is a genuinely employee-friendly practice, and it's worth asking about during the offer stage. Coinbase, Pinterest, and several other companies popularized extended exercise windows, and more startups are adopting them.

Be aware: if you have ISOs and don't exercise within 90 days of leaving, they convert to NSOs. This means you lose the favorable ISO tax treatment. Extended exercise windows are great for optionality, but the ISO conversion is a real tax cost to consider.

A Decision Framework

Here's how I'd think through the exercise decision, step by step. First, calculate the total cost: (strike price times number of shares) plus estimated tax impact. Can you afford to lose this entire amount? If no, don't exercise — or exercise only what you can afford to lose.

Second, assess the AMT impact if you have ISOs. Use a tax calculator or work with a CPA to estimate whether exercising will trigger AMT. If the spread is small enough to stay under the AMT exemption, that's a strong argument for exercising now.

Third, evaluate the company's trajectory. Is it growing steadily with a clear path to liquidity? Or is it struggling? If you believe the company will succeed, exercising early locks in better tax treatment. If you're uncertain, waiting preserves your cash.

Fourth, consider your time horizon. If the company is 3-5 years from an IPO, early exercise starts the long-term capital gains clock. You need to hold for at least one year after exercise (and two years after the grant date for ISOs) to qualify for long-term capital gains rates. Exercising early gives you the best chance of qualifying.

Fifth, don't go it alone. A tax advisor who understands startup equity can model your specific situation and potentially save you more than their fee in the first year. This is one area where professional advice genuinely pays for itself.

The Bottom Line

The exercise decision is one of the most consequential financial choices a startup employee makes. Early exercise with an 83(b) election can save you a fortune in taxes, but it puts real cash at risk. Waiting preserves your cash but can result in a massive tax bill at the worst time. The right answer depends on your personal financial situation, your confidence in the company, and the specific mechanics of your options. Don't default to either extreme — think it through with real numbers.