They can't take it away arbitrarily, but unless you're in a good personal financial position there's a good chance you'll lose it anyway.

The shares are yours, but the company reserves the right to buy them back at the lower of the current price and price you paid for them, which it does when you leave.

http://stockoptioncounsel.com/blog/standards-ownership-canth...

Why are you saying something like it is always true when it is only true given a certain clause is present? It says right in your link that that's only possible when your employment contract says it's possible. Seems dishonest of you.

I never saw anything like this when I worked at an early stage startup, and it's obviously something an employee who reads their employment agreement would ask to be taken out. I'd never work at a company with that clause.

>>> "Some startups"

This is necessary for stock options to work properly. The whole point is to make sure people want to stay and make a profitable company, not that they ditch the instant the stock passes some threshold.

On the other hand, this can lead to disaffected employees who are only staying with the job because they are waiting for their options to mature.

so, the way stock options work properly is that you can work to build a company, and if management blows the revenue, or fires you a month before exit, you get nothing of value out of it?

Most stock options expire within a few months after separation. And, if the present valuation is high, the one separated will have to come up with the cash to buy the options and pay the alternative minimum tax. If the company is private and uncooperative, they can sometimes effectively prevent you from exercising your vested options.

To clarify your comment for other readers: stock options and equity are not the same, and are handled differently upon termination.

If they have a call option on your stock (read your agreement), they're still not "yours". And it's for a private company you have no control over and probably no anti-dilution clauses on either.