What is the definition of an investment bank?

An investment bank is a financial firm that provides a variety of different services with the most common being:

• Corporate finance and advisory (Investment Banking Division)
• Acting as a broker for clients and even trading its own funds (Sales and Trading)
• Managing assets for clients (Asset Management)

Over the last few decades, the main source of profit for investment banks has gone from advisory to trading with many banks now focusing most of their efforts upon sales and trading.