LONDON (MarketWatch) -- Shares of Bayer AG rose as much as 7% in Frankfurt trading on Wednesday on speculation that Swiss rival Novartis will buy the German pharmaceuticals maker at a hefty premium. Wire services reports in Europe, citing unnamed traders, said Novartis planned to launch an offer valuing Bayer at 70 euros a share, which would value the German giant at 53.5 billion euros ($73.1 billion vs. a current market value of $56.5 billion).
