Under-performance at GLG Partners, the hedge fund firm that Man Group acquired in May last year, lay at the heart of Man Group's trading update this morning, which reported that $6bn has been wiped from its asset base since June.

Man Group, the world's largest hedge fund manager, said it expects its funds under management to have decreased from $71bn to $65bn by September 30. The firm's trading update is for the three months to the end of September but only includes full-month performance for July and August.