Club president Ramon Calderon did not name the new sponsor but said an announcement will be made within a week. The new company will replace BenQ-Siemens, the German mobile phone manufacturer that filed for bankruptcy in September 2006.
Madrid's five-year deal with BenQ, which was due to continue until 2010, was worth €100 million.
Calderon said the new sponsorship deal's fee was "unimaginable" for any other club.
Italian club Juventus presently has the biggest shirt sponsorship deal in football, a five-year deal worth €110 million with oil company Tamoil.
