Nearly everyone is familiar with commercial banks such as Wells Fargo and Bank of America. An investment bank on the other hand exists to provide services to private and public companies. In the beginning the purpose of an investment bank was to help companies raise capital through equity offerings and debt issuance and to advise and assist with mergers and acquisitions. Since then the role of the investment bank has evolved and expanded dramatically. The investment bank can sell equity in the company in the form of a stock offering or they can offer advice on the issuance of debt, or bonds, by the company. As you might imagine, an investment bank often has a broad network of contacts within the financial industry. A good investment bank will be able to use this network to provide detailed market knowledge and guidance, legal advice and investment opportunities on a global, countrywide or regional level.