A Wells Fargo branch is seen in the Chicago suburb of Evanston, Illinois, U.S. on February 10, 2015. REUTERS/Jim Young/File Photo

A 3D-printed logo for Twitter is seen in this picture illustration made in Zenica, Bosnia and Herzegovina on January 26, 2016. REUTERS/Dado Ruvic/Illustration/File Photo

Mayor of London Sadiq Khan speaks at the Chicago Council on Global Affairs in Chicago, Illinois, U.S., September 15, 2016. REUTERS/Jim Young

Mariam Araujo, 25, plays with Lucas, her 4-months old second child and born with microcephaly as they wait for a physiotherapy session in Pedro I hospital in Campina Grande, Brazil, February 17, 2016. REUTERS/Ricardo Moraes/File Photo

A 4-month-old baby born with microcephaly is held by his mother in front of their house in Olinda, near Recife, Brazil, February 11, 2016. REUTERS/Nacho Doce/File Photo

Physiotherapist Jeime Lara Leal does exercises with Lucas, 4-months old, who is Miriam Araujo's second child and born with microcephaly in Pedro I hospital in Campina Grande, Brazil , February 17, 2016. REUTERS/Ricardo Moraes/File Photo

Republican presidential nominee Donald Trump gestures as he speaks to the Economic Club of New York luncheon in Manhattan, New York, U.S., September 15, 2016. REUTERS/Mike Segar

Billionaire activist-investor Carl Icahn gives an interview on FOX Business Network's Neil Cavuto show in New York February 11, 2014. REUTERS/Brendan McDermid