Rallye, the food distribution group, is using the convertibles market to shore up its ownership interests in Casino Guichard Perechon, the French supermarket chain that has just unveiled plans for a secondary share sale.

BNP Paribas and Deutsche Bank on Wednesday morning opened the books on a neat convertible bond for Rallye, which as a result will be able to maintain its 52% ownership in Casino Guichard following the supermarket group's €750m ($706m) secondary offering.