Big businesses transformed the American economy in the late 1800s. Tycoons like Rockefeller and Carnegie created vast corporate empires through strategies like monopolies, cartels, and vertical integration that maximized profits but shut out competitors. This concentration of economic power led to public debate over whether these "robber barons" helped the nation through innovations and philanthropy or harmed society. In response to concerns over abuses, the federal government began regulating corporate power through agencies like the Interstate Commerce Commission and laws like the Sherman Antitrust Act.