The United States Chamber of Commerce (USCC) is a business association advocacy group. It is the largest lobbying group in the United States. The group was founded in April 1912 out of local chambers of commerce at the urging of President William Howard Taft and his Secretary of Commerce and Labor Charles Nagel. It was Taft's belief that the "government needed to deal with a group that could speak with authority for the interests of business." The U.S. Chamber of Commerce claims to represent three million businesses, but this claim is often contested.
https://en.wikipedia.org/wiki/United_States_Chamber_of_Commerce