This page is for people evaluating a startup job offer with ISOs or trying to decide what to do with options they already hold.
If you need the tax mechanics first, read Taxation of RSUs, ISOs & NSOs. This page is about value, expectations, and the questions that matter before you make a decision.
The short version
Startup ISOs often sound more valuable than they turn out to be.
That does not mean they are worthless. It means you should be careful about treating them like cash compensation or comparing them directly to public-company RSUs. In many cases, the likely value of startup options is much lower than the headline numbers suggest.
What an ISO actually gives you
An ISO gives you the right to buy common shares at a stated strike price.
Its value depends on several things:
- how many shares you can buy
- the strike price
- the vesting schedule
- the expiration date
- whether the common stock ever becomes worth meaningfully more than the strike price
Unlike RSUs, vesting alone does not usually create value. If the company’s common stock never rises above the strike price in a meaningful way, the option may end up worth very little or nothing.
Why offer letters can be misleading
Companies often highlight the preferred share price from the latest funding round. That can make an option grant look far more valuable than it really is.
The problem is that employee ISOs are usually for common shares, not preferred shares. Preferred investors often have liquidation preferences and other protections that put them ahead of common shareholders in many outcomes.
That means the fair market value of the common stock can be far below the preferred share price, especially in early-stage companies. A grant that looks impressive when compared with the preferred price may be far less valuable in practice.
What has to go right
For ISOs to become highly valuable, several things usually need to happen:
- the company must keep growing
- the common stock value must rise meaningfully above the strike price
- you must stay long enough to vest or exercise on reasonable terms
- there must eventually be a liquidity event or a market for the shares
If the company raises money on worse terms, sells for less than investors expected, or never reaches liquidity, common shareholders may receive far less than the optimistic story suggests.
Questions to ask
Before accepting or exercising startup ISOs, ask:
- What is the current 409A valuation for the common stock?
- How often is that valuation updated?
- What happens to the options if I leave the company?
- Is there any realistic path to liquidity before an IPO?
- How large are the liquidation preferences on the preferred shares?
- If I exercise, what tax or AMT exposure am I taking on?
When to be especially careful
Get more deliberate when:
- you are leaving the company and facing a short exercise window
- an IPO or acquisition may be approaching
- the exercise would require a large cash outlay
- the tax cost could be meaningful if the stock later falls
ISOs can be valuable, but they are not a substitute for clear thinking. Treat them as a risky, highly conditional part of compensation, not as money already earned.