PepsiCo, the soft drink and snack company, on Monday sued its largest bottler, Pepsi Bottling Group (PBG), in an increasingly fractious struggle over PepsiCo’s unsolicited bid for both PBG and for its second-largest bottler, Pepsi Americas.

PepsiCo is asking a Delaware court to overturn a “poison pill” rights issue defence recently adopted by PBG’s board, on the grounds that it was approved without the presence of two board members representing PepsiCo, which owns 34 per cent of the bottlers’ common stock but controls 40 per cent of its votes.