Published analyses for 14 trace and minor siderophilic elements have been interpreted to indicate a close relationship between the IIIAB iron meteorites and the main group of pallasites. These two groups respectively account for about 32 and 75 % of all irons and pallasites. The composition of the metal in the main group pallasites is very close to that calculated for the liquid after 80 % of a IIIAB iron melt has fractionally crystallized. The pallasites probably formed by the intrusion of residual molten metal from the core into a surrounding olivine mantle.