How are private bankers paid for bringing in new clients?

Excuse the probably very simple question, but how do Private Banker bonuses / comp work?

Basically, if a private banker switched to a new bank, and convinced an old client to come over and invest in one of the bank's investment products, how are they compensated for that? In simpler terms, what does a private banker get for bringing a client with AUM of USD 10 million to a bank and how is this paid. I have never understood this. 

I am not talking about juniors, who earn a certain salary and bonus but those private bankers who bring in new clients. Also not interested in those private bankers who are experts on an asset class, or doing admin work, just those "heavy hitters" who really control client relationships and bring clients in themseleves.