The spin cut-off parameter of the nuclear level density and effective moment of inertia for a large number
of nuclei have been determined from analysis of the experimental data on S-wave neutron resonances and spins of lowlying
levels. Contrary to claims made before, it is shown the spin cut-off parameter differs considerably from their
corresponding rigid body values, and the energy dependence of the effective moment of inertia confirms the interacting
fermion model prediction.