The Australian billionaire sold his stake in RatPac Entertainment, the Los Angeles-based film, television and documentary business he created in 2013 with producer-director Brett Ratner.
The venture had instant success with its first investment in the space adventure film Gravity, starring Sandra Bullock and George Clooney, which earned more than $US700 million at the worldwide box office and scored seven Oscar wins.
Mr Packer offloaded his stake to another billionaire mogul, American businessman Len Blavatnik, who heads conglomerate Access Industries.
Financial terms were not disclosed.
RatPac became a major player in Hollywood, co-financing more than 50 films that picked up 51 Oscar nominations and earned more than $US10 billion in worldwide box office receipts including The Revenant, Birdman, Creed, The Lego Movie, American Sniper, Kong: Skull Island and Godzilla.
RatPac aligned itself with another mogul, Steve Mnuchin’s Dune Entertainment, and they signed a four-year, $US450 million deal with Warner Bros to fund as many as 75 of the studio’s films.
Mr Mnuchin has since become US President Donald Trump’s US Treasury Secretary.
Warner Bros chief executive Kevin Tsujihara on Tuesday welcomed Blavatnik and praised him for his “incredible track record launching really successful business ventures”.
“I’d also like to thank James — he’s been a terrific partner the last three years, having worked with us on a number of key films, including Batman v Superman, Suicide Squad and The Lego Batman Movie,” Mr Tsujihara said.
Mr Ratner will retain his interest in RatPac Entertainment, continue as chief executive and become co-chairman.
Mr Ratner and Mr Packer, who combined their surnames for their venture’s name, ran it from a bungalow on Warner Bros’ Los Angeles studio lot that Frank Sinatra, leader of Hollywood’s legendary Rat Pack, once worked out of. “That is cool — RatPac in Frank Sinatra’s old office,” Ratner told AAP in an interview in 2014.
“There is no brand cooler than RatPac and, by the way, this was all James’s idea.
“He called me up one day and said, ‘You’re Ratner, I’m Packer. We are the only two people aside from Frank Sinatra that can have a company called RatPac.”
RatPac also had plenty of box office flops and critical stinkers, including Jupiter Ascending, Entourage, Pan, In the Heart of the Sea, Storks and Collateral Beauty.