Thomas Cook Group plc is a British global travel company listed on the London Stock Exchange. It was formed on 19 June 2007 by the merger of Thomas Cook AG, itself the successor to Thomas Cook & Son, and MyTravel Group plc. It is a constituent of the FTSE 250 Index.At the time of the merger, 52% of the shares in the new company were held by the German mail-order and department store company Arcandor (the former owner of Thomas Cook AG) and 48% owned by the shareholders of MyTravel Group.