A specific model for the origin of ferromagnetism in Fe is assumed which attributes the origin of the ferromagnetism to the indirect coupling of localized d‐like electrons by a small number of itinerant d electrons. We find that about 5% of the d‐electrons are in itinerant d bands; the other 95% being in d‐bands which are sufficiently narrow that they can be considered localized. Band calculations and Fermi surface measurements strongly support such a model. Using this model we give the scaling rules for the three contributions to the hyperfine field at any solute atom in an Fe, Co or Ni matrix and evaluate some of these contributions. The analysis indicates that the CEP curves for 4s electrons of Co and Ni are similar to that measured for Fe. Thus the origin of ferromagnetism in Co and Ni is also assumed to be due to a small fraction of itinerant d electrons in these metals.