The company said it was paying up to pounds 29.6m for MarMedia Group, a Swedish media specialist. The deal virtually completes its European network, but investing in the US remains high on the agenda.
Chris Ingram, executive chairman, said the company had to have a presence in the US, which has a 40 per cent share of the world advertising market. He said: "I'd like to be there with more than a foothold some time next year."
Mr Ingram said CIA would need to forge alliances with international media buyers as well as make acquisitions to achieve his goal of heading one of the top six media buying points in the world by 2001. Talks are being held with several companies about possible alliances or joint ventures.
The Scandinavian acquisition will be funded in cash and shares, and is conditional on CIA raising around pounds 17m by placing 12.5 million shares at 150p each.
MarMedia's clients, which include Ikea, Toyota and Nestle, will sit alongside CIA's portfolio of advertisers such as Ericsson, Shell, Microsoft, Nike and Swatch.
Dag Ulvegarde, a director and founder of MarMedia, will join the CIA board. Mr Ingram also strengthened the board yesterday with the promotion of Mainardo de Nardis, in charge of CIA's European operations.