The bulk amorphous FINEMET was prepared from ribbon and powder by shock wave compaction. The magnetization of compacts was measured up to 550°C. The Curie and crystallization temperature was 350°C and 495°C respectively. From the magnetization curves of as-compacted and annealed samples measured at room temperature in the external magnetic field up to 1.8 T, the effective anisotropy and the law of approach to saturation was derived The deviation from saturation was ascribed to the stress related structural defects in ribbon compacts with prevailing effect of the point-like defects. In the powder compacts the deviation was caused by the intrinsic magnetostatic fluctuations due to spatial inhomogeneity.