June 14 (Reuters) - Billionaire hedge fund manager Daniel Loeb’s Third Point owns a substantial stake in Vivendi SE and has been invested in the French media giant for some time, a source familiar with the firm’s holdings said on Monday. “The company has yet to see any evidence of a stake being built,” a Vivendi spokesperson said in a statement. Vivendi, controlled by French tycoon Vincent Bollore, last month set out a plan to list its crown jewel and the world’s largest music group Universal Music Group by Sept. 27, in a transaction that will see it distribute 60% of Universal’s capital to its current shareholders. The company had also said it could sell an additional 10% of Universal to an American investor as part of the deal. But activist fund Bluebell Capital Partners and investment fund Artisan partners have raised concerns about the spinoff, decrying the transaction as unfavorable to some investors. $1 = 0.8247 euros Reporting by Eva Mathews, Svea Herbst-Bayliss and Gwenaelle Barzic; Editing by Ramakrishnan M. Our Standards: The Thomson Reuters Trust Principles.