Using magneto-optical methods, we have measured the energy separation between the subbands in a semimettalic InAsGaSb superlattice associated with the InAs conduction band (CB) and the GaSb valence band (VB) as a function of hydrostatic pressure up to 11kBar. The CB-VB energy overlap (Δ) at the InAsGaSb interface is found to depend less on pressure than predicted on grounds of usual assumptions concerning band energy shifts induced by pressure. Also inter-subband coupling has been observed between the bands in different adjacent materials. This coupling is found to lead to anti-crossing in the subband dispersion relation. © 1986.