The billionaire has owned the club since 2003 through his private company, Fordstam. Mega-wealthy Abramovich has invested more than $2 billion in the form of loans.
He oversaw the transformation of the west London team into one of the most successful in English leagues. Earlier this month, Chelsea added the Club World Cup title to the Champions League trophy they won last year.
Players at Chelsea are preparing to face Liverpool in the Carabao Cup final on Sunday.