Britain's WPP Group has won an auction for Grey Global with what sources familiar with the matter said was a cash-and-stock deal worth about £750 million sterling (€1.1 billion).
WPP had been competing with French advertising group Havas and US private equity firm Hellman and Friedman to buy Grey, the world's seventh-largest global advertising firm.
WPP, the second largest advertising company in the world, said it would provide further details in a statement today.
The company owns several media businesses in Ireland including Wilson Hartnell PR, DDFH&B, Ogilvy & Mather and the media buying/planning agency Mindshare.
New York-based Grey, controlled by its 77-year-old chief executive Ed Meyer, was the only independent advertising group left after a 1990s consolidation in which top agencies were snapped up by four leading parent companies. It handles advertising work for clients including Procter & Gamble and Nokia.