Berkshire Hathaway owns 14.2% of American Express. Warren Buffett himself owns almost 5% of the entire credit card company. The Berkshire portion consists of 151,610,700 shares. Buffett’s story with American Express began early in his career—1963—and was Buffett’s first big investment in the aftermath of his father’s death.
What happened was this: A businessman named Tino de Angelis took out loans from American Express, Bank Leumi, and a predecessor to Bank of America. He posted barrels of salad oil inventories as collateral to offer the banks a security interest in exchange for the cash they sent his way, and de Angelis cleverly created fictitious salad oil reports to run one of the largest frauds in American history. He got his hands on $150 million that honest accounting would have rejected (to get a handle on the enormity of the figure, it would be the equivalent of $1.3 billion today and fueled robber baron public policy concerns about one man being able to get his hands on such immense wealth from inventory reports alone). American Express was responsible for $58 million to cover its error in judgment. The price fell almost 60%. Buffett entered.