Stray loss studies were performed for a 3-phase, 3-legged core. Because all 3 legs can be modeled and 3-phase currents used, one would expect greater accuracy for these losses as compared with analytical or 2D finite element analyses. Because anisotropic conductivity and permeability can be modeled in 3D, this presents the opportunity to study the relative effectiveness of shunts made of laminated core steel, which can be stacked flat or on edge. This chapter compares the 3D losses to losses obtained by analytic methods and test results for transformers of various ratings and types. Transformer structural elements such as clamps and tank, where much of the stray loss occurs, are generally made of magnetic steel, which has a small skin depth relative to the thickness of the material. 3D finite element methods are now available for modeling all 3 phases, including the effects of 3-phase flux. Even some approximations must be made to make the calculations tractable.