A spokeswoman for Fitch said: "While we are confident that all our policies and procedures meet regulatory standards, we are moving swiftly to address any issues identified in the report." Meanwhile, a spokeswoman for Moody's added that the company "was committed to complying with the European regulations and effectively managing any potential conflicts of interest as we continue to enhance the performance, processes and transparency that underpin our ratings." Clarification: This story has been updated to include a comment from Moody's. - By CNBC's Catherine Boyle. Twitter: @cboylecnbc.