Goldman Sachs said it would "pursue all appropriate legal remedies without delay" after Bank of Portugal stuck to a decision to keep a loan linked to the U.S. bank in a "bad bank" carved out after the rescue of Banco Espirito Santo (BES).

"The Bank of Portugal's decision not to restore Oak Finance's obligations to Novo Banco is based on factual errors and violates basic principles of due process and fairness," a spokeswoman for Goldman Sachs said.

"We intend to pursue all appropriate legal remedies without delay."