UK mortgage lender Northern Rock provided the most lucrative short-selling opportunity last year, earning investors £240m (€322m), according to new data.

Investors would have made a return of 56%, compared with a gain of 0.3% on the FTSE Eurofirst300 index, according to analysis by Financial News based on Bloomberg data, if they had taken short positions in the five best opportunities identified by data provider Data Explorers and held them for the whole year.