The magnetic hysteresis properties of compacted amorphous, nanocrystalline and crystalline Fe73.5Cu1Nb3Si13.5B9 alloys were measured using the fluxmetric method in the DC mode and in the AC mode over a frequency range of 10 Hz to 1 kHz. The powder material was compacted using the shock-wave technique. X-ray studies showed that the microstructure of the samples remains amorphous during the compaction. The maximum DC flux density of a nanocrystalline sample annealed at 550°C was 0.9 T. The AC flux density decreased from 0.72 to 0.65 T as the magnetizing frequency was increased from 10 Hz to 1 kHz. The corresponding increase in total core losses was 1.42–219 W/kg. The results are interpreted on the basis of plastic deformation and consequent stress-induced anisotropies.