  Production of black holes has been discussed in a variety of extensions of
the Standard Model, and related bounds have been established from data taken at
the Large Hadron Collider. We show that, if the Higgs particle has a fully
gravitational content via the equivalence principle, enhanced cross-sections of
black holes at colliders should be expected within the Standard Model itself.
The case of black hole production by precision measurements at electron
colliders is discussed. The Coulomb repulsion strongly suppresses the related
cross-section with respect to the one based on the hoop conjecture, making the
possible production of black holes still unfeasible with current beam
technology. At the same time, this suggests the reanalysis of the bounds, based
on the hoop conjecture, already determined in hadronic collisions for
extra-dimensional models.
