Credit ratings agencies have been in the firing line since the financial crisis. Much criticism has been directed at the ability of such firms to accurately assess risk, although the agencies argue that the purpose of their ratings has been misunderstood.

Either way, it is widely accepted that the financial industry became overly reliant on the ratings provided by the likes of Standard & Poor's, Moody's and Fitch prior to the credit crisis. Fund research businesses now face similar questions and scrutiny.