Morgan Stanley is an American multinational investment bank and financial services company headquartered at 1585 Broadway in the Morgan Stanley Building, Midtown Manhattan, New York City. With offices in more than 42 countries and more than 55,000 employees, the firm's clients include corporations, governments, institutions and individuals.Morgan Stanley ranked No. 67 in the 2018 Fortune 500 list of the largest United States corporations by total revenue.

The original Morgan Stanley, formed by J.P. Morgan & Co. partners Henry Sturgis Morgan (grandson of J.P. Morgan), Harold Stanley and others, came into existence on September 16, 1935, in response to the Glass–Steagall Act that required the splitting of commercial and investment banking businesses.In its first year the company operated with a 24% market share (US$1.1 billion) in public offerings and private placements.

The current Morgan Stanley is the result of merger of the original Morgan Stanley with Dean Witter Discover & Co. in 1997.Dean Witter's Chairman and CEO, Philip J. Purcell, became the Chairman and CEO of the newly merged "Morgan Stanley Dean Witter Discover & Co."Eventually, the new firm changed its name back to "Morgan Stanley" in 2001.The main areas of business for the firm today are institutional securities, wealth management and investment management.