We note that the valence bands in A 14 M Sb 11 compounds are quite similar, with a single dispersive band centered at the Γ point and flatter, non-dispersive bands below the band extremum (see e.g., Yb 14 MnSb 11 ). The fact that these bands are dominated by Sb-atoms explains why the p-type thermoelectric properties of all A 14 M Sb 11 compounds are similar for the same hole concentration.