IC Bus (originally IC Corporation) is an American bus manufacturer. Headquartered in Lisle, Illinois, IC is a wholly owned subsidiary of Navistar International. Established in 2002 by Navistar through the reorganization of subsidiary manufacturer American Transportation Corporation (AmTran), IC currently produces school buses and commercial-use buses for multiple applications. Though sharing Illinois corporate headquarters with its parent company, IC vehicles are produced at the Tulsa, Oklahoma facility opened by AmTran in 1999, ending assembly operations in Conway, Arkansas in 2010.