[en] Highlights: • Hartree-Fock (HF) exchange effect is studied on the CO adsorption on B12N12. • By an increase in the %HF, the LUMO level is nearly constant. • While the HOMO level is strongly stabilized, expanding gap. • By the %HF increment the volume of the all structures decreased. • Sensitivity of the B₁₂N₁₂ is slightly increased toward CO molecule by %HF. We studied the effect of Hartree-Fock (HF) exchange percentage of a density functional on the adsorption properties and electronic sensitivity of the B₁₂N₁₂ nanocluster to CO molecule. It was found that by an increase in the %HF, the LUMO level is nearly constant while the HOMO level is strongly stabilized, expanding the HOMO-LUMO gap (E_g). Also, the volume of the all structures decreased and the sensitivity of the B₁₂N₁₂ is slightly increased to CO molecule. For the pristine B₁₂N₁₂ cluster, the B66 and B64 bonds are about 1.43 and 1.49 Å at 10% HF, and 1.23 and 1.26 Å at 100% HF, respectively. The HF exchange between 10–20% may predict an accurate E_g for the B₁₂N₁₂ system. We concluded that functionals with a large %HF such as M06-HF, and M06-2X may significantly overestimate the E_g, and bond strength. We obtained a parabolic relationship between the %HF and the adsorption energy of CO molecule on the B₁₂N₁₂ cluster. Also, an increase in the %HF predicts a larger charge transfer from the CO molecule to the cage.