ArcelorMittal, the world’s biggest steel producer, sought to raise $3bn from an offer of stock and convertible bonds after announcing a net loss of $1.1bn in the first quarter due to the global steel downturn.

Lakshmi Mittal, chairman and largest shareholder, said he would subscribe to at least 10 per cent of the placing, which will consist of $2.5bn of new shares and $500m of convertible notes due in 2014. His stake will fall from 45 per cent to just over 40 per cent.