America is the toughest nut for Nokia to crack. When Olli-Pekka Kallasvuo, Elop's predecessor, took the helm in 2006, he made one big promise -- he would focus fully on fixing Nokia's problems in the United States, spending a week each month on it. But Nokia has continued to lose market share in the U.S.; the company now has well under 10 percent of the market, lagging behind rivals such as Apple, Samsung and LG.