Cadbury shares rose over 2 percent to a high of 817 pence before last trading up 1.9 percent at 816p at 0930 GMT, or nearly 13 percent above Kraft's bid valued at 9.9 billion pounds ($16.4 billion).
Kraft made its official cash and shares bid for Cadbury earlier this month, which currently values Cadbury shares at around 723p, and may raise its bid if other rival bidders emerge, said a source familiar with the situation late Sunday.
Most of the remaining large players in the worldwide confectionery industry -- U.S.-based Hershey Co
It looks as if just about everyone in the confectionery industry is looking at Cadbury. Kraft is still our favorite, but talk of rival interest is pushing Cadbury's shares higher, said one industry analyst.
(Reporting by David Jones; Editing by David Holmes)