The Club World Cup is an annual competition that sees seven clubs, usually winners of their continental tournaments, compete in a knock-out event. Spain's Real Madrid have won three of the last four editions.
The report said FIFA would have a 51 percent stake in the venture.
SoftBank declined to comment on the report.
The New York Times reported this week that FIFA President Gianni Infantino told his top board last month that a fund of investors from the Middle East and Asia wanted to pay about $25 billion to buy an expanded version of the Club World Cup as well as the rights to a proposed global league for national teams.
(Reporting by Aditi Prakash in Bengaluru; Editing by Peter Rutherford)
