Did Mark Denning have a conflict of interest?
One of the world's leading fund managers has been forced to resign after the BBC discovered evidence suggesting he had broken investment rules.
Mark Denning helped to manage more than $300bn (£229bn; €265bn) of investors' money at Capital Group.
BBC One's Panorama uncovered evidence that suggests he was secretly acquiring shares for his own benefit in some of the same companies as his funds.
Mr Denning, who had worked at the firm for 36 years, denies any wrongdoing.
Lawyer Michael Ruck explains how Mr Denning's conduct could represent a serious conflict of interest.
Panorama: Can You Trust the Billion Pound Investors? is broadcast on Monday at 20.30