We construct the low energy effective theory of composite quarks, leptons, and Higgs bosons for a supersymmetric preon model and study the effects of renormalization-group based radiative corrections. The study on the evolution of scalar masses for avoiding color and charge breakings leads us to conclude that Yukawa couplings are bounded from above. The implementation of electroweak symmetry breaking requires that only the purely dynamical symmetry breaking should be needed for the model, but the combined scheme of dynamical and radiative symmetry breaking as well as the purely radiative symmetry breaking scheme be disfavored. Our analysis of [Formula: see text] including radiative effects shows that, should a discrepancy be found between the observed and the theoretical value of [Formula: see text] after experimental determination of supersymmetric particle masses, it would imply that the complete quark–lepton universality in the supersymmetric preon model does not hold either for the Yukawa couplings, or for the condensates, or for both.