Pratt and Rogers became Rockefeller's partners. Rogers, in particular, became one of Rockefeller's key men in the formation of the Standard Oil Trust. Pratt's son, Charles Millard Pratt, became secretary of Standard Oil. For many of his competitors, Rockefeller had merely to show them his books so they could see what they were up against and then make them a decent offer. If they refused his offer, he told them he would run them into bankruptcy and then cheaply buy up their assets at auction. However, he did not intend to eliminate competition entirely. In fact, his partner Pratt said of that accusation "Competitors we must have ... If we absorb them, it surely will bring up another."[52]
Instead of wanting to eliminate them, Rockefeller saw himself as the industry's savior, "an angel of mercy" absorbing the weak and making the industry as a whole stronger, more efficient, and more competitive.[65] Standard was growing horizontally and vertically. It added its own pipelines, tank cars, and home delivery network. It kept oil prices low to stave off competitors, made its products affordable to the average household, and, to increase market penetration, sometimes sold below cost. It developed over 300 oil-based products from tar to paint to petroleum jelly to chewing gum. By the end of the 1870s, Standard was refining over 90% of the oil in the U.S.[66] Rockefeller had already become a millionaire ($1 million is equivalent to $33 million[39] in 2024 dollars).[67]