The substitution of Fe with Co and B with Si is investigated in a series of high induction Fe84B13Nb2Cu1 amorphous alloys. The as-quenched melt-spun alloys are structurally amorphous in wheel side and a mild crystallites alongwith amorphous phase in air side. The alloy with 35 at% Co addition depicts improved thermal stability, saturation induction and coercivity, and the optimal combination of soft magnetic properties is achieved for an extended annealing temperature range. The additional 10 at% Si deteriorates soft magnetic properties. © 2019 Elsevier B.V.