The European Commission seized documents from several major banks on Tuesday, marking the intensification of a world-wide law-enforcement probe into how key interest rates are set, the Wall Street Journal said, citing people familiar with the situation.
European officials are investigating an interest rate called the Euro Interbank Offered Rate, or Euribor, the newspaper said, citing the people.
WSJ said the European regulators are delving into the possibility that financial companies tried to manipulate the Euribor rate. It said the full list of financial firms raided on Tuesday wasn't clear.
Euribor rates are traditionally the main gauge of unsecured interbank euro lending and a mix of interest rate expectations and banks' appetite for lending.
A spokeswoman for the European Commission wasn't immediately available for comment.
(Reporting by Megha Mandavia in Bangalore; Editing by Gary Hill)