
From Wikipedia,
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.) is referred to as the "sell side."
Dealing with the pension funds, mutual funds, hedge funds, and the investing public who consume 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.
An investment bank is split into the so-called Front Office, Middle Office, and Back Office.
The leading investment banks including
Morgan Stanley Dean Witter and
Goldman Sachs are said to be in the bulge bracket.
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