He was chairman of Kahn Brothers Group, Inc., the privately owned investment advisory and broker-dealer firm that he founded with his sons, Thomas and Alan, in 1978.

[1] He made his first trade—a short sale of a copper mining company—in the summer of 1929, months before the famous market crash in October of the same year.

He attended the City College of New York and went on to serve as the second teaching assistant to Benjamin Graham at Columbia Business School.

Kahn was also a former director of Teleregister Corp., Hugo Stinnes Co., Grand Union Stores, Kings County Lighting, West Chemical, and Willcox & Gibbs.

In a magazine article in 2002, he was quoted as saying: "I'm at the stage in life where I get a lot of pleasure out of finding a cheap stock," adding that his research still pushed him to work evenings and weekends.

His son Thomas, then and still currently president of Kahn Brothers Group, said, "My father continues to research ideas and talk to companies.