The Austrian-Canadian billionaire founder of a global car parts firm is suing family members claiming mismanagement of family assets and trust funds.
Frank Stronach, 86, filed the suit in an Ontario court this month, claiming C$520m ($398m; £300m) in damages.
The suit names his daughter Belinda, her two children, the Stronach Group CEO Alon Ossip and others.
None of the claims made in the lawsuit have been tested in court.
It alleges "a complete break-down" of relationships within the family, according to Thoroughbred Daily News, which first reported on the matter.
A statement released by Mr Stronach's legal team says the business tycoon and his wife Elfriede Stronach "regret having to commence proceedings" against family members.
"They only did so as a last resort, after having made considerable efforts over a period of almost two years to resolve the matters at issue on a consensual basis.
Who is Frank Stronach?
Born in Austria to a working-class family, he spent many years in Canada. There, he made his fortune building car parts firm Magna International into a global company from its modest beginnings in his Toronto garage.
He later entered the world of horseracing, creating what became the Stronach Group, which operates a number of horse-racing and horse-breeding companies, including the Santa Anita racetrack in California and Gulfstream Park racetrack in Florida.
Mr Stronach was also briefly involved in politics in Austria.
The Austrian-Canadian business titan formed a political party in his country of birth before quitting politics just over a year later.
What does his daughter say?
His daughter, Belinda Stronach, 52, is president of the Stronach Group and a former member of parliament in Canada.
Ms Stronach said in a statement to media that family relationships and business could be a challenging mix: "My children and I love my father. However, his allegations are untrue and we will be responding formally to the statement of claim in the normal course of the court process."
How have others reacted?
Mr Ossip said in a statement made through spokesman Paul Deegan that the claims made in the lawsuit were "baseless and are not grounded in fact or reality".
"Alon has always honoured his obligations and acted in good faith to preserve and grow the Stronach family's assets and to protect the interests of all members of the family," he said.
He said this dispute should be resolved between family members.
On Thursday, the Stronach Group said that "while we regret the tension that exists within the Stronach family, it remains business as usual" for the organisation.