Desperate move. No artist (especially one that's big) should be managed by a company that has other notable clients. When you're at a certain status level, your manager should be someone who either manages you only...or you should be the biggest name on their client list so that you're their top priority. You want them to be able to devote almost ALL of their time and effort to YOU. Usher sharing representation with Bieber and Grande is only going to compromise him.