  We study quantum spin Hall insulators with local Coulomb interactions in the
presence of boundaries using dynamical mean field theory. We investigate the
different influence of the Coulomb interaction on the bulk and the edge states.
Interestingly, we discover an edge reconstruction driven by electronic
correlations. The reason is that the helical edge states experience Mott
localization for an interaction strength smaller than the bulk one. We argue
that the significance of this edge reconstruction can be understood by
topological properties of the system characterized by a local Chern marker.
