Klaus Wübbenhorst is used to a challenge. The marathon-running chief executive of GfK, who completed the Hamburg marathon in 3hr 15min, is planning to take on the New York marathon in September.

That, however, may not be the most difficult task facing him at the moment. He is competing with Sir Martin Sorrell, the chief executive of WPP, in the battle for TNS, the market research group. And Sir Martin rarely fails to get what he wants.

Dr Wübbenhorst is faced with the challenge of convincing GfK shareholders that making a counter-bid for TNS is a wise move. The German market research group's shares fell nearly 12 per cent after the news that it had joined forces with a third party to trump WPP's bid.

Dr Wübbenhorst, who is also a university lecturer, has been the chief executive of GfK since January 1, 1999, and has been a member of the group's board since 1992, when he also joined the company as its finance director. At the time, he also had responsibility for personnel, purchasing and production. He is contracted to remain GfK's chief executive until 2012, according to the group's 2007 annual report.

Last year, Dr Wübbenhorst received a total remuneration package of €1,363,300, made up of a base salary of €571,000 and a bonus of €792,300.

Dr Wübbenhorst, 52, began his career in 1984 at Bertelsmann, the German media giant, where he stayed for six years before becoming managing director of Druck-und Verlagsanstalt Wiener Verlag in Himberg, near Vienna. Before joining GfK, he was also a member of the management board of KBA-Planeta.

He graduated with a degree in business administration in 1981 from the University of Essen. He also obtained a doctorate from the Technische Hochschule, Darmstadt. In 2005, Dr Wübbenhorst was awarded the title of honorary professor by Friedrich-Alexander- University in Erlangen-Nuremburg.

GfK has about 9,300 employees working in 115 operating companies in more than 100 countries, but, despite its international presence, insiders say that the group remains “very German”, with strong ties to its native country and its roots.

The company was founded in 1934 by Wilhelm Vershofen. The company contines to use the motto of its founding father - “Let the voice of the consumer be heard” - which it says is the foundation of its success.