William Avery Rockefeller Jr. was an American businessman and financier. Rockefeller was a co-founder of Standard Oil along with his elder brother John Davison Rockefeller. He was also a part owner of Anaconda Copper, which was the fourth-largest company in the world by the late 1920s. Rockefeller started his business career as a clerk at 16. In 1867, he joined his brother's company, Rockefeller, Andrews & Flagler, which later became Standard Oil. The company was eventually split up by the Supreme Court in 1911. Rockefeller also had a significant involvement in the copper industry. In 1899, Rockefeller and Standard Oil principal Henry H. Rogers joined with Anaconda Company founder Marcus Daly to create the Amalgamated Copper Mining Company, which later returned to the name Anaconda Copper.

Standard Oil Company, Inc., was an American oil production, transportation, refining, and marketing company that operated from 1870 to 1911. At its height, Standard Oil was the largest petroleum company in the world, and its success made its cofounder and chairman, John D. Rockefeller, among the wealthiest Americans of all time and among the richest people in modern history. Its history as one of the world's first and largest multinational corporations ended in 1911, when the U.S. Supreme Court ruled that it was an illegal monopoly.