I think it is a lot more than 20% to pay the tax man since the gain on the exercise is considered regular income. This could be a big problem if the stock is st

I think it is a lot more than 20% to pay the tax man since the gain on the exercise is considered regular income. This could be a big problem if the stock is still illiquid on the day of exercise. And if you later couldn't get the private valuation price the loss is capital loss and only $3000 per year can be used to offset regular income.