Research Focus We are working on the development of generally applicable new density functionals that are based on wave-function methods but in which the favourable scaling behaviour of standard DFT is conserved. This will require the combination of the method with fast numerical algorithms to extend the applicability to large systems. A first step in this direction has already been made by introducing a new orbital-dependent exchange-correlation functional derived from the fluctuation-dissipation formula with exact Kohn-Sham exchange.