Abstract$$U(1)^\prime $$
U
(
1
)
′
extensions of the standard model with generation-dependent couplings to quarks and leptons are investigated as an explanation of anomalies in rare B-decays, with an emphasis on stability and predictivity up to the Planck scale. To these ends, we introduce three generations of vector-like standard model singlet fermions, an enlarged, flavorful scalar sector, and, possibly, right-handed neutrinos, all suitably charged under the $$U(1)^\prime $$
U
(
1
)
′
gauge interaction. We identify several gauge-anomaly free benchmarks consistent with $$B_s$$
B
s
-mixing constraints, with hints for electron-muon universality violation, and the global $$b \rightarrow s$$
b
→
s
fit. We further investigate the complete two-loop running of gauge, Yukawa and quartic couplings up to the Planck scale to constrain low-energy parameters and enhance the predictive power. A characteristic of models is that the $$Z^\prime $$
Z
′
with TeV-ish mass predominantly decays to invisibles, i.e. new fermions or neutrinos. $$Z^\prime $$
Z
′
-production can be studied at a future muon collider. While benchmarks feature predominantly left-handed couplings $$C_9^{\mu }$$
C
9
μ
and $$C_{10}^{\mu }$$
C
10
μ
, right-handed ones can be accommodated as well.
B-anomalies from flavorful U(1)$$'$$ extensions, safely
