Hedge funds are notoriously fussy about who they hire. At London-based GSA Capital, Doug Ward, the partner responsible for recruitment, speaks to around 1,500 candidates per year - and sometimes won’t hire a single one.

The firm, which spun out of Deutsche Bank in 2005, ranks thousands of candidates, most of whom are quantitative analysts, from the past 10 years on a database that measures metrics including problem solving skills and mathematical ability. The goal is to find the top coders who can make the firm more money. As Ward put it, “good hires can really move the needle”.