Data that have proved useful in developing a rich understanding of monetary developments at the ECB include all aspects of the MFI balance sheet: the components of M3; the counterparts to M3 (notably loans and credit); holdings of M3 deposits by institutional sector; and contributions to M3 deposits by the residency of the issuing bank.
In particular, in deepening our understanding of money demand, one promising approach is to distinguish between deposits held by households, non-financial corporations and nonmonetary financial institutions. This obviously requires sectoral monetary data.