the logo of italian oil and gas group eni is seen on the facade of its headquarters in rome italy december 23 2017 reutersalessandro bianchifile photo milan june 9 reuters  italys eni enimi said on thursday it planned to list its retail and renewables business renamed plenitude on the milan stock exchange eni which owns 100 of plenitude said it would retain a majority stake after the initial public offering of its unit