The results of tight-binding calculations on the subvalent silver-rich oxide Ag5Pb2O6 indicate that the correct valence state. formulation is (3)(infinity)[Ag-5](Pb24+O62-)-Pb-4+. The odd electron per formula unit in [Ag-5](4+) is delocalized over the entire silver substructure, namely over both the silver atoms making up the Kagome layer and those of the chains which are threaded through it. Although this state of affairs results in a half-filled silver s band at the Fermi level, the structure does not distort to lower symmetry because of the three-dimensional nature of the Fermi surface. Both the electronic density of states and the Fermi surface, although complicated, may be readily understood as a combination of contributions from the layer and chain atoms of the silver substructure. It is suggested that doping the material with fluorine (to give Ag5Pb2O5F) should be a good test of the half-filled band for the oxide, since filling it with one more electron should lead to a semiconductor.