  We explore the impact of asymptotically safe quantum gravity on the Abelian
gauge coupling in a model including a charged scalar, confirming indications
that asymptotically safe quantum fluctuations of gravity could trigger a
power-law running towards a free fixed point for the gauge coupling above the
Planck scale. Simultaneously, quantum gravity fluctuations balance against
matter fluctuations to generate an interacting fixed point, which acts as a
boundary of the basin of attraction of the free fixed point. This enforces an
upper bound on the infrared value of the Abelian gauge coupling. In the regime
of gravity couplings which in our approximation also allows for a prediction of
the top quark and Higgs mass close to the experimental value [1], we obtain an
upper bound approximately 35% above the infrared value of the hypercharge
coupling in the Standard Model.
