The story
Aeroporto Guglielmo Marconi di Bologna and Società Azionaria Gestione Aeroporto Torino had a cross ownership until February 2014, which AdB sold their minority interests (4.13%) to 2i Aeroporti and Tecnoinvestimenti (a subsidiary of Tecno Holding) for €5.166 million.
From Wikipedia’s article on Aeroporto Guglielmo Marconi di Bologna (company), shared under CC BY-SA 4.0.5