http://en.wikipedia.org/wiki/Standard_Oil#Monopoly_charges.2C_anti-trust_litigation_and_breakupIn 1904, Standard controlled 91% of production and 85% of final sales. Most of its output was kerosene, of which 55% was exported around the world. Standard's plants were about as cost efficient as competitors'. After 1900 it did not try to force competitors out of business by underpricing them.<11> The federal Commissioner of Corporations concluded that beyond question, Standard's dominant position in the refining industry was due "to unfair practices, to abuse of the control of pipe-lines, to railroad discriminations, and to unfair methods of competition."<12> Standard's market share fell gradually to 64% by 1911. It did not try to monopolize the exploration and pumping of oil (its share in 1911 was 11%).
In 1909, the US Department of Justice sued Standard under federal anti-trust law, the Sherman Antitrust Act of 1890, for sustaining a monopoly and restraining interstate commerce by:<13>
That's the only real time I know of the government trying to regulate and reign in big oil...and it didn't last.