  Fermi-edge singularity changes in a dramatic way in a nonequilibrium system,
acquiring features which reflect the structure of energy distribution. In
particular, it splits into several components if the energy distribution
exhibits multiple steps. While conventional approaches, such as bosonization,
fail to describe the nonequilibrium problem, an exact solution for a generic
energy distribution can be obtained with the help of the method of functional
determinants. In the case of a split Fermi distribution, while the `open loop'
contribution to Green's function has power law singularities, the tunneling
density of states profile exhibits broadened peaks centered at Fermi
sub-levels.
