Rest-frame L_X versus (vs.) L_6 μm luminosity diagram for the unambiguous AGN i.e. those with intrinsic X-ray 2–10 keV luminosity L_X > 10⁴² erg s^-1. The X-ray luminosity is uncorrected for absorption, while the mid-IR luminosity includes both the torus and the star-formation component. The black and the red circles correspond to the Compton-thick and Compton-thin sources in the AGN (L_X > 10⁴² erg s^-1) sample of Brightman & Nandra (2011a). The shaded area denotes the Compton-thick regime based on the average L_X/L_6 μm relation (corrected for obscuration) found for local AGN by Lutz et al. (2004) scaled down assuming a 3% fraction of reflected emission from the backside of the obscuring screen in the 2–10 keV band. The dispersion in this relation is  ≈ 0.7 dex for type-2 AGN. The blue lines show the luminosity-dependent average relation for Compton-thick AGN based on the COSMOS AGN assuming a 3% (solid-line) and a 1% (dashed-line) fraction of reflected emission. Only one Compton-thick source (2MASX J15504152) lies above the nominal Compton-thick regime as defined by the Fiore et al. (2009) average relation assuming a 3% reflection.