The competitive landscape and business structure of global investment banks has changed fundamentally following the 2008 global financial crisis(GFC). With the bankruptcy, acquisition or shift to bank holding companies of the leading pure investment banks, such as Lehman Brothers, Merrill Lynch, Bear Stearns, Goldman Sachs and Morgan Stanley, there are now fewer investment banks than ever before. In addition, the business model of the surviving investment banks has changed significantly in the post GFC era. While the focus prior to the GFC was on the trading business for high income and ROEs, there is now a strategic emphasis on stabilization of income through diversification of business lines. A particularly notable change post GFC is the entry of major investment banks into the retail finance market. This is taking place especially in wealth and asset management, as well as in new business entry areas such as internet banking. This report looks at the historical development of investment banks, from its inception in the 1930s with the passage of the Glass Steagall Act up to the GFC, and following the GFC to the present. The report aims to look at the major changes in the business model of the major investment banks along with the underlying drivers.