  We propose an economical model to address the mass hierarchies of quarks and
charged leptons. The light generations of the left-handed fermions form
doublets under an $ \mathrm{SU}(2) $ flavor symmetry, which is gauged. The
generational hierarchies emerge from three independent rank-one contributions
to the Yukawa matrices: one is a renormalizable contribution, the second is
suppressed by a mass ratio, and the last by an additional loop factor. The
model is renormalizable and features only a handful of new fields and is
remarkably simple compared to typical completions of gauged flavor symmetries
or Froggatt-Nielsen. The model has a rich phenomenology, and we highlight
promising signatures, especially in the context of $K$ and $B$ meson physics.
This includes an interpretation of the latest $B^+ \to K^+ \nu \bar \nu$
measurement from Belle II.
