MILAN (Reuters) - Shares in Italy's biggest commercial broadcaster Mediaset (>> Mediaset SpA) rose 8.2 percent on Wednesday, hitting their highest level since August 2015 and then triggering an automatic trading suspension.

After French media group Vivendi (>> Vivendi) raised its stake in Mediaset from 3 percent to 25.6 percent in just over a week, the Milan-based TV group has more than doubled in value since the beginning of December and is on course for its biggest monthly gain since its listing 20 years ago.

Mediaset said on Tuesday it risked being paralysed by Vivendi's aggressive stake-building and said it would all measures to protect its assets.

(Reporting by Danilo Masoni and Giulia Segreti, editing by Valentina Za)

Stocks treated in this article : Vivendi, Mediaset SpA