The Sherman Antitrust Act (1890) was the first major U.S. law designed to limit monopolies and protect competition by making it illegal for companies to form trusts or agreements that restrained trade or controlled entire industries. At first, the law wasn’t enforced very strongly, but during the Progressive Era, President Theodore Roosevelt changed that — which is why he became known as a “trust buster.” Roosevelt didn’t oppose all big businesses; instead, he believed in distinguishing between