Man Group’s proposed takeover of rival hedge fund GLG Partners has been dealt its first blow as two credit ratings agencies announced they may downgrade the firm over concerns about liquidity and successful integration.

In a statement today, Moody's Investor Services said it was placing Man's Baa1 issuer rating on review with a negative outlook. The announcement follows Standard & Poor's decision yesterday to place the London-based hedge fund's BBB+/A-2 rating on credit watch for a possible downgrade "by one or two notches" over coming months.