Samsung notified WPP Group over the weekend, executives familiar with the situation said.
Samsung said WPP agencies "will provide ongoing support for Samsung's core global brand marketing programs in strategic markets around the world."
The company said WPP agencies have already begun work on the account, with the aim of breaking an ad campaign in early 2005.
The review pitted WPP against Publicis Groupe and incumbents Foote Cone & Belding and Initiative, part of Interpublic Group of Cos.
"It was strange," one executive said. "After one of the longest reviews in history, Samsung sent an e-mail."
The e-mail popped up on WPP executives' Blackberries on Saturday.
WPP agency networks J. Walter Thompson and Berlin Cameron/Red Cell will share the creative portion of the account, working together on ideas and using JWT as a delivery system. To handle media, Group M's MindShare is expected to form an international partnership with Samsung's in-house agency, Cheil Communications. In a non-Olympics year, Samsung spends about $400 million on branding and product advertising.
Although WPP has won the global branding business, it is unclear whether local product assignments may still be done by other agencies.
The review had been held up repeatedly due to Samsung's painstaking decision-making process, complicated by the vast number of people involved, from Cheil and different levels of Samsung's corporate and staff executives around the world. The departure in September of Samsung's executive vice president and global marketing officer, Eric Kim, to become Intel's chief marketing officer further delayed the decision.
WPP won the other major holding company review of the year, the $600 million HSBC account, in June.