TL;DR Answer Box
ISO vs RSU taxes comes down to timing, cash needs, and risk. ISOs can create powerful long-term capital gains outcomes, but they may trigger Alternative Minimum Tax (AMT) and require out-of-pocket cash to exercise. RSUs are simpler, but they are taxed as ordinary income at vesting and can create a withholding gap for high earners. Last updated: February 18, 2026.
Introduction
Equity compensation is the cherry on top tech companies use to attract talent and keep you around long enough to build something meaningful.
It is also where a lot of high earners get surprised. Not because equity is “bad,” but because the taxes, timing, and cash flow mechanics are very different from salary.
This guide breaks down ISOs and RSUs, the two most common forms of equity compensation in tech. You will walk away knowing what gets taxed, when it gets taxed, and what you should do before a big vest, exercise, or sale.
Equity compensation in tech, the short version
There are a lot of acronyms in the equity world. But for planning, you can simplify it fast.
- Options (like ISOs): you usually have the right to buy shares at a fixed price. You decide if and when to exercise. You may need cash to do it.
- Units (like RSUs): you receive shares (or the cash equivalent) when they vest. You do not pay an exercise price, but you do owe taxes.
If you want the full equity compensation landscape, start here: Equity Compensation Explained: How High-Income Professionals Can Maximize Their Wealth.
Incentive Stock Options (ISOs)
How ISOs work
Incentive Stock Options (ISOs) give you the right to buy company stock at a predetermined price after vesting. That predetermined price is your strike price.
Two details matter immediately:
- Vesting schedule: you may vest gradually, or you may have a cliff where a large portion vests at once.
- Expiration window: options can expire. If you do not exercise in time, the opportunity can disappear.
The AMT “bargain element” problem
ISOs have favorable tax treatment under the right conditions. The trade off is complexity.
When you exercise ISOs, you typically do not owe regular federal income tax at the moment of exercise. However, the “bargain element,” which is the difference between the fair market value at exercise and your strike price, may be included in the AMT calculation.
That is why high earners can get hit with a real tax bill on “paper gains” even if they did not sell any shares and did not create liquidity.
If AMT is new to you, read this before you do anything big: What is the Alternative Minimum Tax (AMT) and What You Need to Know.
Qualifying vs disqualifying disposition
Your ISO sale is treated very differently depending on whether you meet the holding period rules.
- Qualifying disposition: if you sell at least one year after exercise and at least two years after grant, gains may be taxed at long-term capital gains rates.
- Disqualifying disposition: if you sell before those timing rules are met, the bargain element is generally treated as ordinary income, and any additional gain beyond that may be capital gain.
This is why “should I exercise” is only half the question. The other half is “how long can I hold,” and “what happens if the stock drops after I exercise.”
ISO planning checklist
If you are a high earner with ISOs, these are the decision points that usually matter most:
- Cash plan: do you have the cash to exercise without breaking your liquidity plan or emergency reserves?
- AMT modeling: what is the estimated AMT impact at different exercise amounts?
- Concentration risk: how much net worth becomes tied to one company after you exercise?
- Exit reality: for private companies, what is your path to liquidity, and what are the risks if a liquidity event takes longer than expected?
- Disposition strategy: are you aiming for a qualifying disposition, or do you expect you may need to sell earlier?
For a more detailed strategy view, see: ISOs Strategy: Avoid AMT & Build Long-Term Wealth.
Restricted Stock Units (RSUs)
How RSUs are taxed at vesting
RSUs are shares granted to you that become yours when they vest. RSUs are simpler than ISOs, but the tax timing is less forgiving.
When RSUs vest, the fair market value of the shares is generally treated as ordinary income. That means it can be subject to federal income tax, payroll taxes, and state taxes (depending on where you live and work).
Here is the part that surprises high earners: withholding is not the same as your actual tax liability. Some companies withhold a flat percentage, which may not cover your marginal rate, especially when RSUs stack on top of a high salary.
What happens when you sell
After vesting, selling creates a second tax event. The sale can create capital gain or capital loss, based on the change in price between vesting and sale.
- Hold for more than one year after vesting: potential long-term capital gains treatment on the post-vesting gain.
- Sell sooner: short-term capital gains treatment may apply on post-vesting gain.
The most practical takeaway: the vesting date sets your cost basis. Everything after that is investment behavior.
RSU planning checklist
For RSUs, the highest ROI planning work usually looks like this:
- Tax reserve: if your company’s withholding tends to be light, build a quarterly reserve so April is not a surprise.
- Sell-to-cover versus hold: decide whether you want to immediately sell some shares to fund taxes and reduce concentration risk.
- Diversification plan: define a repeatable schedule for selling RSUs so you do not end up overexposed to one stock by default.
If you are managing large ongoing vesting, a rules-based plan can reduce decision fatigue. For some high earners, a 10b5-1 plan may be part of that structure: 10b5-1 Plan for RSUs: Diversification.
ISO vs RSU: what is actually “better”?
“Better” depends on your goals, your liquidity, and your risk tolerance. Here is a simple way to think about it.
Simple comparison “table”
- Tax timing: ISOs may push taxes into AMT at exercise and capital gains at sale. RSUs create ordinary income at vesting, plus capital gains or losses at sale.
- Cash requirements: ISOs can require cash to exercise and cash for potential AMT. RSUs do not require an exercise payment, but you still need to plan for taxes.
- Upside profile: ISOs can be powerful if the company grows and you can hold long enough to qualify. RSUs deliver value at vesting, which is more predictable.
- Risk profile: ISOs can increase risk because you may pay cash to buy shares and then face volatility. RSUs can still create concentration risk, but you are not paying to receive them.
- Best fit: ISOs may fit employees at earlier-stage companies who believe in the growth and can manage liquidity and AMT. RSUs may fit employees who prefer simplicity, predictable value, and faster diversification.
What this means for high earners
If you earn $400K to $2M, the real risk is not “tax rates.” It is failing to model the interaction between equity income, withholding, AMT exposure, and concentration risk.
Equity compensation can be a major wealth accelerator. It can also create avoidable mistakes that quietly cost six figures over time, especially when RSUs and bonuses stack in the same year, or when an ISO exercise creates AMT without liquidity.
Common mistakes
- Exercising ISOs without AMT modeling: a paper gain can create a real tax bill.
- Letting RSUs “auto accumulate”: concentration risk grows quietly when you never create a diversification plan.
- Assuming RSU withholding equals taxes owed: for high earners, it often does not.
- Chasing a qualifying disposition without respecting risk: the tax outcome is not worth it if the concentration risk is unacceptable for your household.
- Making equity decisions in isolation: equity comp planning should connect to cash reserves, goal timelines, and tax projections.
Action steps
- Inventory your equity: list grant type, vesting dates, strike price (for options), and any expiration windows.
- Model two scenarios: “sell at vest” versus “hold,” including a realistic view of taxes and concentration risk.
- Set a tax reserve rule: if you have RSUs, decide how you will cover any withholding gap.
- For ISOs, start with AMT exposure: decide what level of exercise fits your liquidity and risk plan.
- Create a written diversification policy: you want a repeatable plan, not a monthly debate.
If you want the option tax mechanics in more depth, read: Stock Option Taxes: How to Keep More of What You Earn.
Key Takeaways
- ISO vs RSU taxes is mostly about timing: exercise and AMT for ISOs, vesting and ordinary income for RSUs.
- ISOs can offer strong long-term outcomes, but only if liquidity, risk, and AMT are planned for.
- RSUs are simpler, but withholding is often not enough for high earners.
- Concentration risk is the silent killer in equity compensation.
- The best equity plan is the one that fits your cash flow, goals, and tax reality.
Facts/FAQ
Are ISOs always better than RSUs?
No. ISOs can be more tax-efficient under the right conditions, but they can also require cash, create AMT exposure, and increase concentration risk. RSUs are simpler and deliver value at vesting, which can be easier to plan around. The “best” answer depends on your liquidity, time horizon, and ability to manage risk.
Do RSUs get taxed twice?
RSUs can feel like they are taxed twice, but it is usually two different tax events. The value at vesting is typically treated as ordinary income. Then, when you sell, any change in price after vesting is capital gain or loss.
What is the AMT bargain element for ISOs?
The bargain element is generally the spread between the fair market value at exercise and your strike price. That spread may be included in AMT calculations even if you do not sell shares, which is why ISO planning should be connected to liquidity planning.
When should I exercise ISOs?
It depends. Exercise decisions should consider expiration windows, AMT exposure, your ability to hold for a qualifying disposition, concentration risk, and the company’s liquidity outlook. Many high earners benefit from modeling multiple exercise amounts instead of treating it as an all-or-nothing decision.
Why is my RSU withholding often not enough?
Because withholding is often a default approach that may not match your marginal tax rate once salary, bonus, and equity stack together. If you consistently owe at tax time, you may need a quarterly tax reserve system or adjusted withholding. Your CPA can help confirm the right approach for your facts.
What should I track for taxes (forms and numbers)?
Track vesting dates and values for RSUs, and strike price, exercise dates, and fair market value at exercise for ISOs. Also keep the brokerage statements that support cost basis reporting. Documentation matters because equity compensation is easy to misreport if the forms are incomplete or the basis is wrong.
Internal Links
- Equity Compensation Explained: Broader map of equity types and how high earners use them.
- ISOs Strategy: Avoid AMT & Build Long-Term Wealth: Practical ISO planning framework and AMT-aware decisions.
- Stock Option Taxes: Option tax mechanics and planning considerations.
- AMT Guide: AMT context for high earners, especially ISO holders.
- 10b5-1 Plan for RSUs: A structured approach to RSU diversification for some situations.
External Links
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If your compensation includes ISOs or RSUs, you do not need more general advice. You need a plan that models taxes, liquidity, and concentration risk together, because that is where the real money is kept or lost.
Start with our guide: Equity Compensation Whitepaper. If you want help translating your specific grants into a clear strategy, Tailored Wealth can help coordinate equity planning with tax planning and a long-term portfolio strategy built around your real goals.