German retailer Metro has rejected a $6.6bn takeover offer from an investment vehicle controlled by Czech billionaire Daniel Kretinsky, arguing it “substantially undervalues” the Düsseldorf-based company. EP Global Commerce, which is controlled by Mr Kretinsky and his Slovakian business partner Patrik Tkac, said on Friday night that it would offer $18.1 in cash for each Metro share it does not already own, and $15.7 for each preference share.