[chollida1]

They are used in Finance, regardless of title, to help entice people to leave a competitor.

Almost everyone in this world works on a decent salary and potentially large bonus model for compensation. To help entice more long term thinking, and hold people to the firm, bonuses vest over 2-4 years.

It's extremely common to have a discussion with a potential new firm about how much money you are walking away from unvested bonuses and for them to just match that bonus number and vesting schedule as a precondition for joining a new firm.