The offer, made by Bank of America, was originally seen as a rescue attempt on the U.S. biggest mortgage lender following the subprime collapse.

SRM Global Fund, a hedge fund with 5 per cent state, complains that the offer “considerably undervalued” Countrywide and said they would vote against any deal.

UK trader Jon Wood leads the group, as well as a similar one in the UK fighting the sale of Northern Rock, and says he plans to urge other large shareholders including Legg Mson, Capital Research and Fidelity to vote against the Bank of America offer.

“We believe that the company is strong and will rapidly return to profit on a standalone basis,” SRM said in a statement.

"SRM considers that the proposed terms considerably undervalue the Company. We also believe that the acceptance by the Company of the proposed terms is inconsistent with statements made by the Company and its officers in the fourth quarter of 2007.”