Less than 18 months ago, Lakshmi Mittal, the billionaire businessman who made his name forging the world's biggest steelmaker, deepened his relationship with RAB Capital. His pledge to invest $200m in RAB's Special Situations fund last May, compounded by a 10 per cent shareholding in the Aim-listed hedge fund group, means the respected head of ArcelorMittal is sitting on a big paper loss.

But for one of the world's richest men, with a net worth estimated by Forbes magazine to be $45bn (£26bn), the 48 per cent slump in the Special Sits fund this year and the 66 per cent fall in the RAB share price will not make much of a dent.