Younger brother to John D. Rockefeller, William started an oil refinery business in 1867 that he and his brother changed to Standard Oil. William also formed the Amalgamated Copper Company to try to control the copper industry that later became Anaconda Copper Company. With interests in copper, railways and public utilities, he branched into finance and built the National City Bank of New York, which is now a part of Citigroup.
