Investment banking
From Wikinvestor
Investment banks profit from companies and governments by raising money through issuing and selling securities in the capital markets (both equity and bond), as well as providing advice on transactions such as mergers and acquisitions. To perform these services in the United States, an adviser must be a licensed broker-dealer, and is subject to SEC (FINRA) regulation. Until the late 1980s, the United States maintained a separation between investment banking and commercial banks. Other developed countries (including G7 countries) have not maintained this separation historically.
A majority of investment banks offer strategic advisory services for mergers, acquisitions, divestiture or other financial services for clients, such as the trading of derivatives, fixed income, foreign exchange, commodity, and equity securities.
Trading securities for cash or securities (i.e., facilitating transactions, market-making), or the promotion of securities (i.e., underwriting, research, etc.) was referred to as the "sell side".
Dealing with the pension funds, mutual funds, hedge funds, and the investing public who consumed the products and services of the sell-side in order to maximize their return on investment constitutes the "buy side". Many firms have buy and sell side components.
References