  We analyze the structure of the non-unitary leptonic mixing matrix in the
inverse seesaw model with heavy singlets accessible at the LHC. In this model,
unlike in the usual TeV seesaw scenarios, thelow-scale right-handed neutrinos
do not suffer from naturalness issues. Underlying correlations among various
parameters governing the non-unitarity effects are established, which leads to
a considerable improvement of the generic non-unitarity bounds. In view of
this, we study the discovery potential of the non-unitarity effects at future
experiments, focusing on the sensitivity limits at a neutrino factory.
