PS

Pershing Square Inc

A publicly traded investment management company that runs the activist investing firm founded by Bill Ackman in 2004. It takes large stakes in big companies and pushes for changes to boost their value, and it went public on the New York Stock Exchange in 2026. The firm is named after Pershing Square Plaza near Grand Central Terminal in New York City, which honors General John J. Pershing, the U.S. Army commander of American forces in World War I.