Mark Johnson, global head of foreign exchange cash trading in London HSBC Holdings Plc, center, leaves federal district court in the Brooklyn borough of New York, U.S., on Wednesday, July 20, 2016.  Federal agents surprised Johnson as he prepared to fly out of New York's Kennedy airport around 7:30 p.m. Tuesday, arresting him for an alleged front-running scheme involving a $3.5 billion currency transaction in 2011. Photographer: Christopher Goodney/Bloomberg via Getty Images