The inclusive decay rate b →ccs¯ is enhanced considerably due to perturbative QCD corrections. We recalculate the dominant part of the NLO–QCD corrections, because they cannot be reconstructed from the literature and we give the full expressions in this paper. Further we include some previously neglected corrections originating from penguin diagrams. Combined with the impressive progress in the accurate determination of input parameters like charm quark mass, bottom quark mass and CKM parameters, this enables us to make a very precise prediction of the corresponding branching ratioBr(b→ccs) ¯ =(23±2)%. This result is an essential ingredient for a model and even decay channel independent search for new physics effects in B decays
