ABB on Friday said it would set aside $850m before tax in the fourth quarter for potential legal and restructuring charges in a surprise profits warning from the Swiss- Swedish engineering group.

The group said it expected to remain profitable in the quarter, in spite of weakening market conditions. Net quarterly profits have reached about $1bn this year: ABB made $738m after tax in the final three months of 2007. Full-year results will be revealed on February 12.