IRVING KAHN
Benjamin Graham's teaching assistant and the oldest known professional investor, still active past age 100
Irving Kahn is perhaps the greatest proof that value investing is a philosophy you live by, not just a strategy. He was Benjamin Graham's teaching assistant at Columbia in the 1930s and kept showing up to the office past 100 years old. He co-founded Kahn Brothers Group in 1978 with his sons, growing it to over $700 million in assets. He shorted stocks before the 1929 crash. The man was contrarian before contrarian was a buzzword.
Net Worth
~$5M–$10M (est.)
Nationality
American
Time Horizon
Long-Term
Risk Appetite
2 / 10
CAREER & BACKGROUND
Kahn started on Wall Street in the 1920s. He worked directly under Benjamin Graham at Columbia University, absorbing value investing at the source.
He was one of the very few investors who had lived through the 1929 crash and positioned for it beforehand. In 1978, he co-founded Kahn Brothers Group with sons Thomas and Alan, growing the firm to over $700 million in assets.
He stayed active as chairman well into his 100s, reportedly still coming into the New York office regularly until shortly before his death at 109.
COMPANIES & ROLES
Kahn Brothers Group (co-founder and chairman, 1978–2015)
INVESTING STYLE & PHILOSOPHY
Deep value. Buy misunderstood or ignored companies at a discount to intrinsic value and hold for years.
Focused on businesses with strong balance sheets, low debt, and predictable cash flows. No interest in hype, momentum, or fast-moving trends.
THE PLAYBOOK
Risk Approach
Very low. Kahn was obsessed with not losing capital.
He built positions slowly, held them for years, and favored boring, predictable businesses over exciting growth stories.
Money Habits
Lived modestly despite decades in professional finance. Prioritized capital preservation above all else.
Believed thorough research before every purchase was non-negotiable.
BIGGEST WIN
Shorting stocks ahead of the 1929 crash — one of the very few investors who saw it coming and protected capital during the worst market collapse in history.
BIGGEST MISTAKE
Kahn was famously private about losses. He acknowledged that value investors always have misses but treated them as tuition, not failures.
Specific errors were rarely disclosed publicly.
FINANCIAL PHILOSOPHY
Buy cheap and wait. He believed time was the investor's greatest edge.
Holding quality assets long enough always let the market catch up to reality. He was deeply suspicious of leverage and speculation.
FAMILY & PERSONAL LIFE
Married Ruth Kahn. Three children: sons Thomas and Alan, who co-founded Kahn Brothers Group with him, and actress and comedian Madeline Kahn.
EDUCATION
City College of New York. Served as teaching assistant for Benjamin Graham's Security Analysis course at Columbia University, absorbing the full value investing curriculum firsthand over several decades.
BOOKS & RESOURCES
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QUOTES (6)
Never borrow money to invest. It destroys patience, which is the only real edge a value investor has.
The stock market is a mechanism for transferring wealth from the impatient to the patient.
You must be willing to hold a stock for years, sometimes decades, before it reaches its full value.
Benjamin Graham taught me that the key to investing is buying a dollar for fifty cents.
I have seen many booms and busts. The lesson is always the same: prices always come back to value.
NETFIGO SCORE
Proprietary 5-dimension investor rating
Risk Appetite
Contrarian Index
Track Record
Accessibility
Time Horizon
Related Profiles
Investors
Benjamin Graham
Graham was Kahn's professor and mentor at Columbia University starting in the 1930s. Kahn served as his teaching assistant and absorbed the Security Analysis framework directly at the source.
Walter Schloss
Walter Schloss was another Graham protege who worked alongside Kahn. Both men spent decades practicing pure value investing with remarkable consistency.
Warren Buffett
Both were Graham disciples. Buffett and Kahn shared the same intellectual lineage and both cited Graham as the foundation of their investment philosophy.
Head-to-Head
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