 Topsøe owned the company "Haldor Topsøe" until 1972 when the Italian company "Snamprogetti" took over 50% of its shares.In 2007, he bought it back and it is now owned to 100% by the Topsøe family.Besides his own process, Topsøe has also worked as among Chairman of the Scandinavian Airlines and Danish Air Lines and been member of the board of directors of among "Kampsax", "Incentive A/S", "De forenede Bryggerier", "Haand i Haand" and "Philips".