What is the ruling of the Sharia on giving a responsible employee a percentage of the returns from projects he assigns to our company, and is this considered bribery or illicit gain?

What an employee does, taking money in exchange for awarding projects, falls under bribery, which is forbidden both to give and to receive. However, if you are the most deserving of the project and cannot obtain it except by paying a bribe, then there is no blame upon you for paying it. This is considered a form of conciliation and a دفعًا للظلم (warding off injustice), while it remains a bribe on the part of the employee.