Earlier quoted context omitted.
> in the US, you only get taxed when you sell the shares That's not quite correct with regards to US tax law at least. You can get taxed on the spread between the price you pay and the "fair market value" of the shares received. It's quite possible to get nailed with an insane tax bill in situations like this. You can end up in a situation where a company raises money at high valuations, and that spread is high, gene…
> leading to a horror story of being taxed on a percentage of the millions of dollars you supposedly got but never realized a dime from. If the shares a complete loss and liquidated that way, you also have a capital loss for the millions of dollars which can be applied against income for tax purposes; this may end up somewhat less than offsetting the tax bill depending on your other income because of tax rates; you d…
Also, we have AMT (alternative minimum tax) which gets triggered by this kind of scenario--exercise and hold--and really ends up screwing you due to outdated but not updated calculations that assume anyone making over 150k or so is "rich".