" In the 1920s, he decided that it was cheaper to drill for oil than to buy the overvalued shares of other oil companies. After the 1929 stock market crash, he completely changed tack; he saw that oil shares were selling at a great discount to assets, and he turned to prospecting for oil on the floor of the stock exchange—in "

― Daniel Yergin , The Prize: The Epic Quest for Oil, Money, and Power