The influence of tensile stress annealing on the magnetic properties of amorphous alloys is reported for ribbons belonging to the pseudo ternary system (FeCoNi)75Si15B10. Ribbons of compositions (Co1-xFex)75Si15B10are susceptible to stress annealing in the whole composition range . A very large easy ribbon axis anisotromy can be produced in the range whereas the largest hard ribbon axis anisotropy is producable in the composition range around x=0.15. Ribbons of compositions [CO1-x(Fe0.5Ni0.5)x]75Si15B10are found susceptible to stress annealing only in the range . In all the compositions the induced easy ribbon axis anisotropies are irreversible whereas the hard ribbon axis anisotropies are recoverable with activation energies ≥ 1.55 eV.