Nine months after [consultant and new hire] Paul McDowell received the phone call that would change his life, another Bridgewater employee collapsed into tears. It wasn’t ordinary crying, but a full-on meltdown, complete with chest heaving, gasping for breath, and animalistic sobbing.

Thirty-something, with shoulder-length blond hair sagging limply, Katina Stefanova wasn’t used to being in this position. She was, as widely viewed inside the firm, one of Ray Dalio’s favourites – and she was usually the person who made other people cry. Her colleagues called her the Ice Queen.