Comparison between black-hole masses computed on the basis of the MgIIλ2798 Å and the Hβ lines for the XBS AGNs where both lines are included in the spectrum. Red points represent sources with a relatively high S/N (>5) around the line of interest and with lower statistical error bars (<0.2 dex) while grey points are objects with lower S/N spectra and/or larger error bars. As reference we plot the relation 1:1 (solid line), while the two dashed lines represent a scatter of 0.5 dex.