Christine Lagarde, managing director of the International Monetary Fund (IMF), left, and Sheryl Sandberg, billionaire and chief operating officer of Facebook Inc., react during a panel session during the World Economic Forum (WEF) in Davos, Switzerland, on Wednesday, Jan. 18, 2017. World leaders, influential executives, bankers and policy makers attend the 47th annual meeting of the World Economic Forum in Davos from Jan. 17 - 20. Photographer: Jason Alden/Bloomberg via Getty Images

Christine Lagarde, managing director of the International Monetary Fund (IMF), left, and Sheryl Sandberg, billionaire and chief operating officer of Facebook Inc., react during a panel session during the World Economic Forum (WEF) in Davos, Switzerland, on Wednesday, Jan. 18, 2017. World leaders, influential executives, bankers and policy makers attend the 47th annual meeting of the World Economic Forum in Davos from Jan. 17 - 20. Photographer: Jason Alden/Bloomberg via Getty Images