From Longman Business Dictionarydemutualizede‧mu‧tu‧a‧lize /ˌdiːˈmjuːtʃuəlaɪz/ (also demutualise British English) verb [intransitive, transitive] FINANCE if a MUTUAL COMPANY, such as a life insurance company or a BUILDING SOCIETY, demutualizes or is demutualized, it obtains the agreement of the people who invest in it, or are insured by it, to become a LIMITED COMPANY with shareholders, listed on the stockmarketDuring the last decade, many building societies and life insurers demutualised and were floated on the stock market. —demutualization (also demutualisation British English) noun [countable, uncountable]There has been a massive expansion in share ownership caused by privatisations and demutualisations.