British advertising giant WPP Group lifted the lid on its $4.7 billion (€5.2 billion) agreed takeover of US rival Young & Rubicam yesterday in a deal that will create the world's biggest advertising group.

Fleshing out an outline deal agreed earlier in the week, WPP said the takeover would give its shareholders two-thirds of the combined group and Young & Rubicam shareholders one-third, in what will be the largest acquisition in the history of advertising.

The deal puts WPP back ahead of US advertising heavyweights Omnicom and Interpublic, creating a $15 billion one-stop marketing shop for mega clients such as Ford, Mattel, Kraft Foods, Unilever and Sears.

As agreed earlier, Young & Rubicam shareholders will be offered 0.835 new WPP American depository receipts or 4.175 new WPP ordinary shares for each Young & Rubicam share, valuing Young & Rubicam shares at $53 each for a total $4.7 billion, based on Thursday's closing prices.

WPP said the deal would create significant savings with at least $30 million of cost synergies identified to date, and the London-based advertising group expects the takeover to be earnings enhancing in the first full year.

After the close of the transaction - which was unanimously approved by both boards - Mr Thomas Bell will be named chairman of Young & Rubicam while its Y&R finance director, Mr Mike Dolan, will be named chief executive, with headquarters remaining in New York.