  We present the results of a study to determine the co-evolution of the virial
and stellar masses for a sample of 83 disk galaxies between redshifts z = 0.2 -
1.2. The virial masses of these disks are computed using measured maximum
rotational velocities from Keck spectroscopy and scale lengths from Hubble
Space Telescope imaging. We compute stellar masses based on stellar population
synthesis model fits to spectral energy distributions including K-band
magnitudes. We find no apparent evolution with redshift from z = 0.2 - 1.2 in
the relationship between stellar masses and maximum rotational velocities
through the stellar mass Tully-Fisher relationship. We also find no evolution
when comparing disk stellar and virial masses. Massive disk galaxies therefore
appear to be already in place, in terms of their virial and stellar masses, out
to the highest redshifts where they can be morphologically identified.
