Theresa May, U.K. prime minister, speaks during a Bloomberg Television interview at the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images

Theresa May, U.K. prime minister, speaks during a Bloomberg Television interview at the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images

Theresa May, U.K. prime minister, gestures as she speaks following a Bloomberg Television interview during the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images

Theresa May, U.K. prime minister, gestures as she speaks following a Bloomberg Television interview during the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images

Theresa May, U.K. prime minister, reacts during a Bloomberg Television interview at the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images

Theresa May, U.K. prime minister, reacts during a Bloomberg Television interview at the World Economic Forum (WEF) in Davos, Switzerland, on Thursday, Jan. 19, 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: Simon Dawson/Bloomberg via Getty Images