Efficient Frontier will manage 100% of Tiscali's marketing search spend across Yahoo!, Google and Microsoft.
Using its bid optimisation and tracking technology, the Efficient Frontier search engine marketing team will manage the campaign strategy and provide a range of tactical services to help Tiscali optimise its entire paid search engine marketing campaign.
Helen Harris, marketing director for Tiscali UK, said: "Efficient Frontier has the ability to scale to our paid search needs, which is imperative for future growth.
"Increasing competition and changes in the marketplace meant we needed to rethink our search engine marketing in order to achieve the next level in ROI."
Efficient Frontier's portfolio management technology automates and optimises bid management using complex algorithms mirroring those used on Wall Street to achieve a higher level of return on investment across large-scale campaigns.
David White, general manager of Efficient Frontier, said: "Search marketing campaigns will never become simpler. The landscape of Google, Yahoo! and Microsoft is becoming increasingly complex and opaque."