[eyer2016]

From an employer's perspective, they don't owe you anything. This is a good thing for them, because when your company gets acquired by another company which has different policies than your company, they won't owe you a dime. While, if your company has a policy of 20 days off and your company got acquired, they owe you $$ amounting to the PTO days you haven't used up.

Source: happened in my previous company but the acquisition happened right after my 8 week vacation, so I didn't get any $$.

Having said that, I also was very lucky to have a good manager who really didn't mind how much vacation I was taking as long as the work was getting done.