Colourful, charismatic and youthful; are not adjectives often associated with private bankers, let alone very senior Swiss private bankers.

So the arrival in 2018 of Boris Collardi at Pictet, the largest and grandest of Geneva’s private partnership banks, almost certainly caused many eyebrows to be raised within the private banking and wealth community.

Throughout his career, first at Credit Suisse and then at Julius Baer, which he joined initially as chief operating offi...