  It is possible, and for several reasons attractive, to explain a collection
of recent anomalies involving $b\rightarrow s\mu\mu$ processes with a
$Z^{\prime}$ gauge boson coupled only to the third family in the weak
eigenbasis. From this premise, requiring cancellation of all gauge anomalies
(including mixed and gravitational anomalies) fixes a unique charge assignment
for the third family Standard Model fermions, which is simply proportional to
hypercharge. After a brief discussion of some general features of anomaly
cancellation in $Z^\prime$ theories, we discuss the phenomenology of such a
`Third Family Hypercharge Model', which is subject to a trio of important
constraints: (i) $B_s-\bar{B}_s$ mixing, (ii) lepton universality of the $Z$
boson couplings, and (iii) constraints from direct searches for the $Z^\prime$
boson at the LHC. Finally, in gauging third family hypercharge, this model
forbids all Yukawa couplings (at the renormalisable level) save those of the
third family, leading to a possible explanation of the heaviness of the third
family.
