Who agrees bonuses?

Financial Regulator Matthew Edlerfield took up his post in 2010.

We are now informed he has decided to waive his entitlement to a bonus of €100,000.

Why would a person who has been employed for three years or less and leaves at his own request be entitled to a bonus of €100,000? This may be another example of why so many bank employees are in receipt of such high salaries and bonuses.