Dean Witter Reynolds was an American stock brokerage and securities firm catering to a variety of clients. Prior to the company's acquisition, it was among the largest firms in the securities industry with over 9,000 account executives (ranking third in the US in 1996) and was among the largest members of the New York Stock Exchange. The company served over 3.2 million clients primarily in the U.S. Dean Witter provided debt and equity underwriting and brokerage as mutual funds and other saving and investment products for individual investors. The company's asset management arm, Dean Witter InterCapital, with total assets of $90.0 billion prior to the acquisition, was one of the largest asset management operations in the U.S.

Dean Witter Reynolds was founded in 1978 as the merger of Dean Witter & Co. and Reynolds Securities (with Dean Witter acquiring Reynolds), which was then the biggest merger in the history of Wall Street. The company was acquired by Sears in 1981, and was renamed "Dean Witter, Discover & Co." in 1993 when Sears spun off the company. The company also owned Discover Card.

In 1997, Dean Witter, Discover & Co. merged with investment banking house Morgan Stanley to form "Morgan Stanley Dean Witter & Discover Co.". The combined firm later dropped the "Discover Co." name in 1998 and further the "Dean Witter" name in 2001.

For many years, the company used the corporate slogan, "We measure success one investor at a time", which was later adopted by Morgan Stanley.

Prior to its merger with Morgan Stanley, Dean Witter Reynolds was a diversified financial services organization that provided a broad range of investment and consumer credit and investment products and services. Dean Witter operated in two lines of business: securities (including investment banking) and credit services and its operations were primarily focused on the U.S.

The following is a summary of the financial results of Dean Witter prior to its merger with Morgan Stanley:

Dean Witter's traditional business was as a full-service securities brokerage. The company maintained a network of over 9,000 account executives. DWR was among the largest members of the New York Stock Exchange and was a member of other major securities, futures, and options exchanges. Dean Witter offered a broad range of securities and savings products that were supported by the firm's underwriting and research activities as well as order execution. Closely related to its securities business, Dean Witter provided investment consulting services to individual investors. The firm managed approximately $10.4 billion of assets in its consulting business as of the end of 1996. Within its securities business, Dean Witter focused on three segments:

Dean Witter also operated as an investment banking firm, even before its merger with Morgan Stanley. Like many of its peers, Dean Witter provided a range of advisory services to corporate clients including mergers and acquisitions, divestitures, leveraged buyouts, restructurings and recapitalizations. The Company generally did not commit capital to merchant banking transactions.