Utilize the input text as a context reference, choose the right relationship between 'Airbus Group' and 'ATR' from the options.
Options: platform, owner of, location of formation, operator

Industry sources have said Airbus Group is exploring increasing its stake in tandem with BAE Systems as part of a wider move that could see Airbus cede its 50 percent share of turboprop maker ATR to its joint-venture partner Finmeccanica.
owner of