Knight-Swift Transportation Holdings Inc. is a publicly traded, American motor carrier holding company based in Phoenix, Arizona. It is the fourth largest trucking company in the United States. The company's primary subsidiaries are truckload carriers Knight Transportation, Swift Transportation, Midnite Express and, since July 2021, less than truckload carrier AAA Cooper. In January 2022, the company expanded its LTL footprint with the acquisition of Midwest Motor Express. In July, 2023 Knight-Swift acquired truckload carrier US Xpress. Wikipedia