Investment banking is a field of banking that aids companies in acquiring funds. In addition to the acquisition of new funds, investment banking also offers advice for a wide range of transactions a company might engage in.

Traditionally, banks either engaged in commercial banking or investment banking. In commercial banking, the institution collects deposits from clients and gives direct loans to businesses and individuals. In the United States, it was illegal for a bank to have both commercial and investment banking until 1999, when the Gramm-Leach-Bliley Act legalized it.

Through investment banking, an institution generates funds in two different ways. They may draw on public funds through the capital market by selling stock in their company, and they may also seek out venture capital or private equity in exchange for a stake in their company.

An investment banking firm also does a large amount of consulting. Investment bankers give companies advice on mergers and acquisitions, for example. They also track the market in order to give advice on when to make public offerings and how best to manage the business' public assets. Some of the consultative activities investment banking firms engage in overlap with those of a private brokerage, as they will often give buy-and-sell advice to the companies they represent.

The line between investment banking and other forms of banking has blurred in recent years, as deregulation allows banking institutions to take on more and more sectors. With the advent of mega-banks which operate at a number of levels, many of the services often associated with investment banking are being made available to clients who would otherwise be too small to make their business profitable.

Careers in investment banking are lucrative and one of the most sought after positions in the money-market world. A career in investment banking involves extensive traveling, grueling hours and an often cut-throat lifestyle. While highly competitive and time intensive, investment banking also offers an exciting lifestyle with huge financial incentives that are a draw to many people.