Comment by prostoalex

Talk to the stock admin at your company. They will provide you with an exercise form.

> can I use the check date as "exercise" date, meaning that I'll be sure the valuation for AMT purposes will still be the one of the Series B

Correct, it's whatever date you'll have on the exercise form, but still, talk to the stock admin for the most recent common stock valuation.

You don't have to disclose your departure, your ISO exercise is an independent event and can happen at the advice of your tax advisor.