Magneto-impedance (MI) effects have been observed for amorphous Fe73.5Nb3Cu1Si13.5B9 ribbon which has been excited by an a.c. magnetic field parallel to the length of the ribbon. Maximum relative change in MI as large as -99% was observed which has never been reported before. The relative change in MI, when plotted against scaled field was found to be nearly frequency independent. A phenomenological formula for magneto-impedance, Z(H), in a ferromagnetic material, is proposed based on Pade approximant to describe the scaled behavior of MI.