Information: - Aktiengesellschaft (abbreviated AG ) is a German word for a corporation limited by share ownership (i.e. is owned by its shareholders) and may be traded on a stock market. The term is used in Germany, Austria, Switzerland, South Tyrol and for companies incorporated in the German-speaking region of Belgium. It is also used in Luxembourg, though the French-language equivalent, "Societe Anonyme", is more common. - CIMIC Group Limited (formerly known as Leighton Holdings prior to April 2015) is a leading international contractor. It is active in the telecommunications, engineering and infrastructure, building and property, mining and resources, and environmental services industries. It has operations in Australia, South East Asia, New Zealand, and the Middle East. Leighton Holdings changed its name to CIMIC Group Limited. - Hochtief Aktiengesellschaft is a German construction company based in Essen, North Rhine-Westphalia, Germany. Hochtief is Germany's largest construction company and operates globally, ranking as one of the largest general construction companies in the United States through its Turner subsidiary, and in Australia through a 53.43% shareholding in CIMIC Group. In 2010 it employed more than 70,000 employees across five corporate divisions. One of these, Hochtief Concessions, is a major airport operator. The others are involved with construction project planning, finance, construction and operation. Work done in 2010 was 23.23 billion, with more than 80% coming from operations outside Germany. - Hochtief Concessions GmbH is a German business , fully owned subsidiary of the Hochtief Group and is responsible for the development and implementation of concessions and operator projects . Its business areas include airports , roads , social infrastructure / public - sector building construction and further public - private partnership ( PPP ) projects handled together with subsidiaries Hochtief AirPort and Hochtief PPP Solutions . What is the relationship between 'hochtief concessions' and 'aktiengesellschaft'?
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