John D. Rockefeller

John D. Rockefeller built Standard Oil into the most powerful corporation in American history and, in the process, invented the modern monopoly. By 1880, Standard Oil controlled roughly 90 percent of U.S. oil refining capacity — achieved through relentless negotiation, predatory pricing, secret railroad rebates that his competitors were denied, and the systematic absorption or destruction of rivals. Rockefeller framed it not as ruthlessness but as order: the replacement of "ruinous competition" with rational, efficient management of an industry he believed was otherwise ungovernable.

Standard Oil's reach extended across pipelines, railroads, and refineries in a vertically integrated empire that extracted profit at every point in the supply chain. Ida Tarbell's investigative series in McClure's Magazine, published from 1902 to 1904, exposed the company's tactics to a national audience already primed for reform and supplied the evidence that built political will for antitrust action. In 1911, the Supreme Court ordered Standard Oil broken into 34 separate companies. The breakup paradoxically made Rockefeller richer — he held shares in all the successor entities, and their combined value soon exceeded Standard Oil's.

Rockefeller's philanthropy matched his business operations in scale and method. He gave away approximately $540 million during his lifetime, funding the University of Chicago, Rockefeller University, and the foundation that still bears his name. He lived to 97, spending his last four decades dispensing money with the same deliberate focus he had once applied to accumulating it. At his peak around 1913, his wealth represented nearly 2 percent of the entire U.S. economy — a concentration of private capital the country has never seen before or since.