The Standard Oil Company was an American oil producing, refining, and marketing company founded by John D. Rockefeller in 1870. It quickly grew to dominate the oil industry in the United States, controlling about 90% of the country's oil refineries and pipelines at its peak. This immense power allowed Standard Oil to set prices and influence the market significantly. However, its monopolistic practices led to public outcry and legal challenges. In 1911, the U.S. Supreme Court ruled that Standard Oil was violating antitrust laws, resulting in its breakup into 34 smaller companies. This landmark decision reshaped the oil industry and set a precedent for regulating monopolies in America.