Velocity versus decay index of Fe II at t₀+15 days for GRB-SNe and ordinary type Ic-BL SNe from the Gold and Silver samples. Velocities have been computed from the power law (PL) and broken power law (BPL) fits. A sample of type Ic SNe from Modjaz et al. (2016) are shown for comparison purposes. Both ordinary type Ic-BL SNe and GRB-SNe have higher velocities than the type Ic SNe population, but there is no clear distinction between the GRB-SN and ordinary type Ic-BL SN velocities.