The two most senior executives at CDC Ixis, the French investment banking subsidiary of Caisse des Depots et Consignations (CDC), have resigned in a dispute over merger plans.

Isabelle Bouillot, chairman of CDC Ixis and Gerard Barbot, president and chief operating officer of the bank, have both quit the company. The firm cited "differences of opinion on the development of CDC Ixis", but would not comment further.