How was John Rockefeller able to control the oil industry?

John D. Rockefeller was able to control the oil industry primarily through the formation of the Standard Oil Company, which utilized aggressive business practices such as horizontal integration and vertical integration. By acquiring rival companies and controlling the supply chain from production to distribution, he significantly reduced competition and lowered costs. Additionally, Rockefeller negotiated favorable rates with railroads for transporting oil, further solidifying his dominance. His strategic use of trusts also allowed him to maintain control over a vast network of oil-related businesses.