Man Group has become the second prominent hedge fund manager this month to have had its credit rating downgraded, as poor performance and redemptions in the sector cast increasing uncertainty over the health of the industry.

Ratings agency Standard & Poor's said yesterday that it had lowered its long-term counterparty credit rating on Man Group from A- to BBB+, and affirmed Man's short-term counterparty credit rating as "A-2" with a negative outlook.