Efficient Frontier replaces Zed Media to manage campaigns across Google, Yahoo! and Microsoft Life Search in the UK.
The credit card and savings company said that it will use Efficient Frontier's team of search marketing experts and their predictive modelling technology to maximise the sales uplift from search campaigns across Capital One's products.
Capital One has dramatically reduced its use of direct mail, having been a top three user of the channel in the UK, to focus on digital marketing.
Earlier this year , its supplier of prospect mail data and database infrastructure services.
David White, general manager of Efficient Frontier, said: "Search marketing is a highly complex environment, demanding sophisticated bid management algorithms coupled with the expertise of market analysts and marketers. We are delighted Capital One has selected us as their full service search provider."