Longtime Hollywood dealmaker Marvin Davis has reportedly offered $15 billion for

Vivendi's

(V) - Get Report

media properties. At least one report says the overture was rebuffed.

The news sent Vivendi's shares up 12% to $13.07 in the Instinet premarket session.

Davis, who once ran 20th Century Fox and who has become a fixture on the Los Angeles social scene, reportedly is in discussions for financing with private equity heavyweights Texas Pacific Group and Bain Capital, as well as a number of banks. His offer, which also includes the assumption of $5 billion in debt, would be for assets including Universal Studios, Universal Music, Vivendi's cable networks and its theme-park operation.

A source close to the company told

Reuters

the offer has been turned down because the assets aren't for sale.

As is customary in Hollywood, Barry Diller has emerged as a key arbiter of the deal. Diller, who worked and clashed with Davis at Fox in the 1980s, is believed to have veto power on the sale of certain Vivendi assets because of restrictions he negotiated last year when Vivendi acquired cable and film assets from his

USA Interactive

(USAI) - Get Report

for $11 billion. Diller is also co-chief executive of Vivendi's entertainment properties.

A source told

The Wall Street Journal

that Diller would be strongly opposed to cooperating with any bid by Davis. Davis' group believes it can get around the Diller restrictions and hopes to retain the operations' existing management.