Not my experience. When my company was acquired by Yamaha (about 5 years ago) title to my stock was transferred immediately. My payment for that stock was scheduled over a two year period but my title was gone on day one. A lot of upper management received new contracts to work for Yamaha, but they had no other rights to any ownership.Commonly, sellers at the top director level remain at positions for a stated period of time, unusually measured in years.
Stock is released to them on a schedule over that time period that makes up much of the payment that they can turn into cash at those scheduled times. But they have to be employed there, as I understand. They get an initial large cash amount at the front.