Leading provider of audit, tax, and consulting for the middle market. RSM US LLP is a leading U.S.-based audit, tax, and consulting firm focused on serving the middle market across the United States and Canada. It operates as the U.S. member firm of the global RSM International network. Founded in 1926 as I.B. McGladrey Company in Cedar Rapids, Iowa, the firm rebranded to RSM US LLP in 2015 after multiple structural evolutions. Headquartered in Chicago, Illinois, RSM US employs approximately 16,800 professionals across offices in the U.S., Canada, India, and El Salvador. The firm offers services including audit and assurance, tax, management consulting, risk advisory, technology consulting, financial advisory, and legal consulting. It is ranked the fifth-largest accounting firm in the U.S. by Accounting Today as of 2025.