A zirconium-based bulk metallic glass, Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1), and its composite, Zr56.3Ti13.8Cu6.9Ni5.6Nb5.0Be12.5 (β-Vit), were subjected to planar impact loading. A surprisingly low amplitude elastic precursor and bulk wave, corresponding to the elastic response of the “frozen structure” of the intact metallic glasses, were observed to precede the rate-dependent large deformation shock wave. A concave downward curvature after the initial increase of the Us–Up shock Hugoniots suggests that a phase-change-like transition occurred during shock compression. Further, compression damage occurred due to the shear localization. The spalling in Vit 1 was induced by shear localization, while in β-Vit, it was due to debonding of the β-phase boundary from the matrix. The spall strengths at strain rate of 2×106 s−1 were determined to be 2.35 and 2.11 GPa for Vit 1 and β-Vit, respectively. © 2002 American Institute of Physics.