Are RSUs and ISOs Really the Same? Not Even Close
Last year, I met a VP at a tech firm who had just exercised about $300,000 worth of ISOs.
The shares never hit their bank account… but the IRS sure did.
A few months later, they were blindsided by an $80,000 AMT bill - all from gains they hadn’t even sold.
They’re not alone. This kind of mistake happens more often than you'd think and it’s almost always preventable.
Every year, high-income execs make costly equity comp mistakes - not because they’re careless, but because no one ever showed them how RSUs and ISOs really work.
In the next few minutes, you’ll learn:
- Why RSUs = income now, while ISOs = control with a catch
- The hidden tax traps most execs overlook
- Smart strategies to stay ahead of the IRS before tax season hits
I. What’s the Difference Between RSUs and ISOs?
Both forms of equity compensation offer upside but their tax rules are night and day.
RSUs (Restricted Stock Units) | ISOs (Incentive Stock Options) | |
Tax Timing | Taxed as ordinary income when they vest | No tax at grant or exercise (but watch for AMT) |
Control | No control over timing of income | Can choose when to exercise and sell |
Tax Benefit | None - fully taxed as income | Favorable long-term capital gains if held properly |
Risk | Surprise tax bill, especially in down markets | AMT if exercised without strategy |
Translation? RSUs are like a bonus check with a leash. ISOs are more like a tax landmine with a long fuse.
II. What Tax Risks Do Most Executives Miss?
These aren’t theoretical issues - they’re real traps that catch smart people off guard.
RSUs: The Silent Tax Hit
The moment your RSUs vest, you're taxed as if you got a bonus whether you sell the shares or not. And if the stock price drops afterward, you could owe taxes on phantom gains you never realized.
ISOs: The AMT Ambush
Exercising ISOs doesn’t trigger regular income tax, but it does show up on your AMT calculation. Exercise too many shares in a high-income year, and you could face a tax bill you didn’t plan for.
Both: The Concentration Risk Trap
When it comes to building wealth, I often think about the saying “you build wealth through concentration but preserve wealth through diversification” and many execs do just that - build wealth in a single concentrated stock… then forget to de-risk. No matter how great your company is, concentration without a plan is a liability, not a strategy.
III. What Should Smart Execs Do Instead?
With RSUs:
- Plan for the tax gap. Your company might only withhold 22–24%, while your real rate could be 37%.
- Sell enough shares at vesting to cover your full tax liability (don’t assume the default covers it).
- Use the proceeds wisely: Think Roth conversions, HSA maxing, or backdoor ROTH IRAs - tax efficiency > parking cash.
- If eligible, consider an 83(b) election for restricted stock - not RSUs - to pay the taxes early at a lower valuation.
With ISOs:
- Exercise in low-income years (e.g., sabbaticals, gap years, pre-exit).
- Use AMT projection software (or a planner) to model how much you can exercise without triggering AMT.
- Diversify intentionally: A pre-set 10b5-1 plan helps you sell gradually without running afoul of insider rules.
Smart execs don’t just think about “how much is this worth?” They ask, “What’s the most tax-smart way to turn this into real wealth?”
IV. What’s in Your Equity Plan?
Most executives don’t need more equity.
They need a better plan.
➜ A plan that accounts for AMT exposure
➜ A plan that protects you from concentration risk
➜ A plan that turns equity into spendable, tax-smart wealth
Download our free Comprehensive Wealth Plan For Executives eBook and schedule a strategy session to make sure your next move is a smart one.
If you would like to discuss your current situation schedule a free 20-minute call with the link below.
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