Michael B. Jordan is a member of the ownership group.
The club announced Tuesday that the takeover has been approved by the league and that the actor has a stake.
Black Knight Football Club has a managing general partner who is also the previous owner of the club.
The firm paid $126 million for a majority stake in the partnership.
The chairman of Bournemouth will be a 77-year-old American who also owns the NHL's Vegas Golden Knights.
According to Cannae's announcement, Jordan will work with the club in areas like global marketing and internationalization.
The next home game for Bournemouth will be against Crystal Palace on New Years Eve.
The football market in Europe is at an attractively priced valuation.
The Vegas Golden Knights can be used to create value at Bournemouth.
We see an opportunity to grow this historic club by investing in its infrastructure and operations with the goal of steering Bournemouth to a long-awaited leading role in the premier league and global football.
Bournemouth is back in the top flight after winning promotion from the second-tier Championship last season and has the smallest stadium in the English top flight.
The club and Cannae didn't include a comment from Jordan.
Demin first invested in Bournemouth in 2011.
Bournemouth is currently in 14th place in the premier league.
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