Market&More had revenues of 13.5m last year and has operations in German, the Netherlands, Belgium and France. Its clients include Procter & Gamble, Interbrew and Danone.
The deal will see Aegis pay an initial consideration of 6m, with an undisclosed deferred consideration subject to performance.
It adds to the acquisitions Aegis made in January -- Chusen Media in Japan, which will become part of the Carat media-buying network, and two US interactive agencies, Lot 21 and Vizium, which become part of the Carat Interactive business.
Doug Flynn, chief executive of Aegis, said: "This acquisition extends our European research network considerably. In just two years, we have grown Aegis Research into the world's 10th largest market research company through major acquisitions in North America, Asia Pacific and EMEA."
Last year, Aegis acquired four European market research firms, including Pegram Walters and MEMRB Custom Research.
Shares in Aegis were trading down by 1.6% this morning, priced at 93.5p. Earlier this week, it was revealed that Ray Kelly, chief executive of Aegis' northern European operations, had been ousted in a management reorganisation.
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