Yahoo will buy the remainder of online advertising exchange Right Media for $680m (£340m) in stock and cash, the search giant has announced.
The company bought a 20% stake of Right Media in October for $45m (£22.5m) and now plans to acquire the remaining 80%, it said.
Right Media offers advertisers and sellers of advertising space a real-time marketplace to buy and sell display advertising on websites. The move expands Yahoo's advertising reach beyond its own network of sites.
It comes hot on the heels of Google's planned $3.1bn (£1.6bn) acquisition of DoubleClick, announced earlier this month as consolidation of the online advertising segment continues.
Right Media was founded in 2003 with investment from Yahoo and others.