Poaching from your competitors is a time-honored practice in financial services, from stock brokers all the way up to M&A kingpins. A lot of legal hours have been--and will continue to be--purchased. There is a sense that the big names can bring over the clients. And many firms take steps to prevent this. Many have "garden leave" agreements for outgoing executives, during which they are barred from contacting colleagues or clients. This is paid leave of course. It basically gives firms an opportunity to limit whatever damage they fear. However, many will argue that most institutions, notably financial sponsors, are pretty loyal to banks, less so to humans. In a sense, the game has become more commoditized and less personality-driven. So a big name doesn't guarantee clients anymore.

For more:
- here's the Investment Dealers Digest article (For FierceFinance readers)