It’s hard to top Rockefeller as a monopolist or philanthropist. While doling out dimes and nickels to the poor, John D. built a sprawling empire by squashing, undercutting, and buying up the competition. Over a two-month period in 1872, Standard Oil absorbed 22 of the 26 petroleum firms in Cleveland, where the company was first headquartered. By 1879, it had about 90 percent of the market for refining petroleum and all but complete control of the U.S. oil industry.
THE STAT: Rockefeller’s fortune peaked in 1912 at $900 million ($19 billion in today’s dollars), but by the time he died, in 1937, he’d given most of his money away to heirs and charities.