On March 9, 1911, the U.S. Supreme Court began hearing oral arguments in Standard Oil Co. of New Jersey v. United States, a landmark antitrust case that challenged John D. Rockefeller's vast petroleum empire. At its peak, Standard Oil controlled an estimated 85–90% of U.S. oil refining and distribution, making it one of the most powerful monopolies in American industrial history.
The case culminated later that year in a ruling that ordered Standard Oil to be broken into 34 separate companies under the Sherman Antitrust Act. Many of today's major energy brands trace their origins directly to this breakup, including Exxon, Mobil, Chevron, Amoco, and Conoco, reshaping competition across the oil and gas industry for generations.
Ironically, the breakup made Rockefeller even wealthier. As shares of the new independent companies surged in value, his personal fortune increased substantially — turning the antitrust defeat into one of the most consequential corporate restructurings in U.S. business history.
