He had counted on a downturn, he later explained, because he was watching traders bid the price of stocks higher and higher.

“I wasn’t smart,” he said in a 2006 interview with National Public Radio, now known as NPR. “But even a dumb young kid could see these guys were gambling. They were all borrowing money and having a good time and being right for a few months, and after that, you know what happened.”

After trading closed for the day, he would ride the subway with Graham to Columbia and sit in on Graham’s investing classes. He became Graham’s part-time teaching assistant.

He scouted potential investments for Graham’s partnership, Graham-Newman, and worked on Graham’s “The Intelligent Investor” (1949).

When Graham retired from his investment partnership in 1956, he recommended Kahn to clients seeking a new adviser. By then Kahn was a partner at Abraham & Co., which was later bought by Lehman Brothers. With sons Alan and Thomas, he parted with Lehman in 1978 to open Kahn Brothers.

Contrarian Investing

Kahn made a practice of poring over technical magazines and scientific journals in search of investment ideas. Like Graham and Buffett, Kahn and his firm sought to be “contrarian in nature,” said Thomas Kahn, whose middle name is Graham. That meant buying securities “that are out of favor and in the dumps for some reason.”

Kahn met his wife, Ruth Perl, at Columbia, where she was studying for her Ph.D. in psychology. They married in 1931; she died in 1996. They raised their three sons at their home in Belle Harbor, in the Queens section of New York. The oldest, Donald, became a math professor at the University of Minnesota. He died last month at 79.

Kahn was a founding member of the New York Society of Security Analysts and was one of the 284 candidates who took the first Chartered Financial Analyst (CFA) examination, in 1963.

Guiding Students