The maximum allowable mean moment-of-inertia I of Mars is 0.3650 MR2 becaue the rate-of-adjustment of the rotation axis is much faster than the rate-of-generation of density heterogeneities, as with any planet. But Mars differs from the other terrestrial planets in that its gravity field is rougher, in the sense of stress-difference implication, and its global tectonics is dominated by one feature, centered on the Tharsis Plateau. Plausible tectonic models of Mars require generation and support that are almost axially symmetry about Tharsis. Hence, unlike other terrestrial planets, Mars likely has two non-hydrostatic components of moments-of-inertia that are nearly equal, and the most probable value of I/MR2 is slightly less than 0.3560. ¿ American Geophysical Union 1989