< PrevNext > 24. IPG Share 2015 U.S.-Booked Air Volume: $133 millionConsolidated U.S. TMC: American Express Global Business TravelIPG's revenue remained mostly static in 2015 at $7.6 billion. On Dec. 31, 2015, the company reported 49,200 employees, of which 19,900 are based in the United States. Growth was driven by increased work with existing clients and new business, with significant contributions from China, India, Singapore and the United Kingdom, according to its 2015 annual report. U.S.-booked air volume increased 60 percent in 2015, when, the advertising holding company acquired majority stakes in four companies—Media Experts in Canada and the Russian affiliates of McCann, MullenLowe and FCB—and acquired the United Kingdom’s Hugo & Cat outright.