May 22 (Bloomberg) -- Cadbury Plc, the world's largest candy maker, rose the most in a week in London trading on speculation about a possible takeover bid.

Cadbury added 2.4 percent, raising its market value to 9.49 billion pounds ($18.8 billion) and posting the seventh-biggest gain on the benchmark FTSE 100 Index. The London-based company spun off its U.S. soft-drink division as Dr Pepper Snapple Group Inc. on May 7.

The confectioner may have to merge with a competitor to retain its market position following Mars Inc.'s $23 billion purchase of Wm. Wrigley Jr. Co., analysts have said. Hershey Co. and Nestle SA have been spoken of by analysts as possible suitors for Cadbury, the maker of Green & Black's organic chocolate and Trident sugarless gum.

``Bid speculation has surrounded the stock since the Dr Pepper sale,'' Scott Sandat, head of sales trading at betting company City Index in London, said by e-mail of Cadbury. Kraft Foods Inc. and its main investor, billionaire Warren Buffett, were cited as ``potentials,'' he said.

Buffett is now on a four-day European tour seeking family-owned companies to buy as he looks for places to put the $35 billion of cash held by his Berkshire Hathaway Inc., saying there's a dearth of U.S. opportunities. He is known for buying privately held companies.

Kraft, the Northfield, Illinois-based maker of Chips Ahoy! chocolate-chip cookies, is expanding overseas and bought French yogurt maker Groupe Danone SA's cookie unit last year. The U.S. company exited the candy market in 2005 with the sale of Life Savers and other confectionery brands to Wrigley.

A Cadbury spokesman who declined to be named refused to comment. Spokeswomen Perry Yeatman of Kraft and Jackie Wilson at Omaha, Nebraska-based Berkshire did not immediately return telephone messages left out of business hours.

To contact the reporters on this story: Loveday Morris in London at lmorris7@bloomberg.net; Adam Haigh in London at ahaigh1@bloomberg.net.

Last Updated: May 22, 2008 12:18 EDT