PORR AG is an Austrian construction group headquartered in Vienna. Listed on the Vienna Stock Exchange, it is among the largest construction companies in Austria and operates internationally across major segments of the construction industry, including civil engineering, tunnelling, building construction, environmental engineering, and facility management. The company traces its origins to 1869, when it was founded as Allgemeine Österreichische Baugesellschaft, making it the oldest company still listed on the Vienna Stock Exchange. The name PORR derives from construction engineer Arthur Porr, co-founder of A. Porr Betonbau, which merged with the company in 1927. Wikipedia