The alloying effects of the like-atom substitution of Ni and Co for Fe on the various properties of Fe 70 B 16.7-Si 8.3 Ta 5 metallic glass are investigated in this present work. New Fe-based bulk glassy alloys, namely Fe 60-x Co x Ni 10-B 16.7 Si 8.3 Ta 5 (at.%; x = 10, 20 and 30) with critical diameters up to 1.5 mm, were made by means of copper mold casting. A new glass-forming ability indicator, viz., the enthalpy of supercooled liquid, has been introduced for assessment of the glass-forming abilities (GFAs) of these Fe-based multi-component alloys. Nano-indentation results indicate that the calculated elastic modulus and hardness of the bulk glassy alloys are lower than those of the Fe 70 B 16.7 Si 8.3 Ta 5 alloy. Among these bulk glassy alloys, Fe 70 B 16.7 Si 8.3 Ta 5 exhibits the large elastic modulus and hardness with values of 178 ± 1 GPa and 12.9 ± 0.1 GPa, respectively. All the bulk glassy alloys exhibit good soft magnetic properties with high saturation magnetization B s * 0.75-1.04 T but low coercive force H c * 0.2-5.2 A/m.