>No, it does not apply to previously taxed assets at all, only to an additional income you made from those assets. I would call that applying to previously tax

>No, it does not apply to previously taxed assets at all, only to an additional income you made from those assets. I would call that applying to previously taxed assets. Unvested RSUs (read: not taxed yet) that gain considerably over many years prior to vesting are still wholly taxed as regular income. Without additional income, there is nothing to be taxed therefore there shouldn't be any confusion as to what I mean by that. Stock options are only one type of equity grants, the other being RSUs which have a cost basis of $0 and therefore the entire sum is subject to income taxes at vesting. Exercising stock options is not free, you must pay to do so at the exercise price which is done using post-tax cash, which again, had to have been taxed as regular income at some point.