We have studied the magneto-Stark effect of exciton states with large wave vectors, significantly exceeding
the wave vector of light. This magneto-Stark effect can be called ‘‘giant’’ in comparison with a similar effect
observed in bulk materials in comparable magnetic fields. In this work, we propose a microscopic model of the
‘‘giant’’ magneto-Stark effect. The model does not contain any free parameters. The numerical results obtained
in the framework of this model quantitatively describe the experimental results published earlier in Ref. S. Y.
Bodnar et al., (2017) for a heterostructure with a wide GaAs/AlGaAs quantum well in a magnetic field