Havas SA (HVSYY) shares surged to a fifteen year high after French billionaire Vincent Bollore said he would pay €2.36 billion his family's stake in the advertising group in order to expand his media empire.

Havas shares rose 10.5% in early trading in Paris to change hands at €9.36 each, the highest since 2002 and well ahead of the €9.25 offer Bollore made late yesterday for the 60% stake controlled by Group Bollore and run by his son, Yannick.

Vivendi SA (VIVHY) shares were also on the move, rising 4.6% to a year-to-date high of €19.25 and valuing the media giant at just under €25 billion ($27.2 billion).

Vivendi said yesterday that, if the offer is accepted, the company would "would enter a new phase of development to accelerate its building of a leading world-class content, media and communications group and will ensure the newly created group a unique positioning in an environment in which content, distribution and communications are converging." 

Paris-based Vivendi not only controls Canal Plus, France's biggest pay-TV company, but also Universal Music Group, the world's third-largest record label.

Bollore told French regulators earlier this year that he was studying the combination of his France-based media interests and confirmed he was looking into the benefits of a merger with Havas. Combining it with Vivendi would create a group market capitalization of about €29 billion.