Christopher Niehaus says he learned “a tough lesson” when he left Jefferies in 2016 for sharing client information using WhatsApp.

“I’ve learned to be very careful about what I write, but psychologically I was just very disappointed with myself for allowing something like this to happen,” said Niehaus, who now runs his own boutique firm Hampstead Advisory. “It was tough for me — I made a mistake and will make sure it never happens again.”