Abstract: The glass forming ability of the (Fe_12/13Y_1/13)_100-xB_x96Nb₂Zr₂ (x=9–26) system was investigated using a series of cluster lines. Three types of clusters, an icosahedron (Fe₁₂Y), a capped Archimedes anti-prism (Fe₈B₃) and a capped trigonal prism (Fe₉B), as well as a binary eutectic (Fe₈₃B₁₇) were considered. Bulk glassy alloy rods of 3 mm in diameter were synthesized using a copper mold suction-casting method. The glass transition temperature was observed for all samples in the boron range of 15.9at%-25.7at%, with the alloy at 15.9at% of boron having the best thermal properties. The ferrous-based bulk metallic glasses (BMG) obtained have high reduced glass transition temperatures with the maximum reaching 0.63 and large supercooled liquid regions with the maximum reaching 111 K. Magnetic testing revealed a large value of coercive force and remanent magnetization, being 11 kA/m and 0.1 T, respectively.