  Models with massive vector leptoquarks, resulting from an $SU(4)$ gauge
symmetry spontaneously broken at the TeV scale, are of great phenomenological
interest given the current "anomalies" in semileptonic $B$ decays. We analyze
the relations between low- and high-energy observables in such class of models
to next-to-leading order accuracy in the $SU(4)$ gauge coupling $g_4$. For
large values of $g_4$, motivated by recent $B$-physics data, one-loop
corrections are sizeable. The main effect is an enhanced contribution at
low-energy, at fixed on-shell couplings. This result has important implications
for current and future high-energy searches of vector leptoquark models.
