  We present a detailed and unique mass budget for the high-surface-brightness
galaxy UGC 463, showing it is dominated by dark matter (DM) at radii beyond one
scale length (h_R) and has a baryonic-to-DM mass ratio of approximately 1:3
within 4.2 h_R. Assuming a constant scale height (h_z, calculated via an
empirical oblateness relation), we calculate dynamical disk mass surface
densities from stellar kinematics, which provide vertical velocity dispersions
after correcting for the shape of the stellar velocity ellipsoid (measured to
have sigma_theta/sigma_R=1.04 +/- 0.22 and sigma_z/sigma_R=0.48 +/- 0.09). We
isolate the stellar mass surface density by accounting for all gas mass
components and find an average K-band mass-to-light ratio of 0.22 +/- 0.09
(ran) ^{+0.16}_{-0.15} (sys) M_{sun}/L_{sun}^{K}; Zibetti et al. and Bell et
al. predict, respectively, 0.56 and 3.6 times our dynamical value based on
stellar-population-synthesis modeling. The baryonic matter is submaximal by a
factor of ~3 in mass and the baryonic-to-total circular-speed ratio is
0.61^{+0.07}_{-0.09} (ran) ^{+0.12}_{-0.18} (sys) at 2.2 h_R; however, the disk
is globally stable with a multi-component stability that decreases
asymptotically with radius to Q~2. We directly calculate the circular speed of
the DM halo by subtracting the baryonic contribution to the total circular
speed; the result is equally well described by either a Navarro-Frenk-White
halo or a pseudo-isothermal sphere. The volume density is dominated by DM at
heights of |z|>1.6 h_z for radii of R > h_R. As is shown in follow-up papers,
UGC 463 is just one example among nearly all galaxies we have observed that
contradict the hypothesis that high-surface-brightness spiral galaxies have
maximal disks.
