The vertical electron detachment energies (VDEs) of 30 MX4- (M = B, Al; X = F, Cl, Br) anions were calculated at the OVGF level with the 6-311 +G(3df) basis sets. The largest vertical electron binding energy was found for the AlF4- system (9.789 eV). The strong VDE dependence on the symmetry of the species, ligand type, ligand-central atom distance, and bonding/nonbonding/antibonding character of the highest occupied molecular orbital was observed and discussed.