Left panel: M_BH-L_bulge relation for the H-band. The black triangles are measurements from Marconi & Hunt (2003) for local galaxies and the dashed line is their best-fit relation. Our 3σ upper limit on L_H,bulge for HE 2158 − 0107 is shown as the red open circle. Middle panel: M_BH-M_bulge mass relation. The black squares correspond to the measurements of Häring & Rix (2004) with their best-fit relation shown as the dashed line. An SED based 3σ upper limit for the stellar mass of the HE 2158 − 0107 is indicated by the red open circle. An independent estimate based on the bulge size in the z-band using the size-mass relation by Shen et al. (2003) is shown as the blue open triangle. The light grey area represents the possible range in M_dyn of the bulge based on the ionised gas kinematics assuming rotational motion of a cold gas disc. Right panel: M_BH-σ_∗ relation for local galaxies with dynamical M_BH measurements. Measurements by Gültekin et al. (2009) are shown as black round symbols and the dashed line indicates their best-fit relation. We used the line dispersion of the [O iii] line (green open square) in the unresolved NLR of HE 2158 − 0107 as a surrogate for σ_∗, following the suggestion by Nelson (2000).