Despite rejection from Rio’s board, Standard & Poor’s said that it has placed BHPB on credit watch with negative implications amid the prospect of a revised bid.

S&P placed BHP’s A-plus/A-1 ratings on credit watch with negative implication while putting Rio Tinto’s BBB+/A-2 credit rating and associated debt on watch with positive implications.

Standard & Poor highlighted potential credit risks of a deal including managing the huge combined entity, regulatory and competition issues and the funding structure.

BHP has been in talks with a small syndicate of banks to secure a debt package worth more than USD 70 billion. Those facilities would be needed to finance the share buyback but BHPB also believes that Rio Tinto’s USD 40 billion financing deal to buy Alcan included a change of control clause and may need refinancing.