Private equity companies are circling Almatis, the German aluminium business, as part of negotiations over a $1.1bn debt restructuring, in the latest sign of trouble for its sovereign wealth fund owner Dubai International Capital.

The Frankfurt-based producer of speciality alumina products, spun out from Alcoa in 2004, has annual sales of about $500m and was bought for about $1.2bn by DIC in November 2007.