Distribution of E_cut as a function of L_2 − 10. Light blue and orange filled circles are estimates from a compilation of local AGN (Bertola et al. 2022, and references therein) and z ≈ 2 − 4 QSOs (Lanzuisi et al. 2019; Bertola et al. 2022). Purple circles are from local super Eddington accreting AGN from Tortosa et al. (2023). Hollow magenta circles are binned averages estimated by Ricci et al. (2018) for a large sample of local AGN from the BAT AGN Spectroscopic Survey (BASS). The HYPERION average E_cut measurement (assuming Γ = 1.9) from our joint analysis is reported as a black star with an inner red circle. Green regions are the forbidden regions (for a slab corona model) due to runaway electron–positron pair production (see Svensson 1984) for log(M_BH/M_⊙) = 8.5 and log(M_BH/M_⊙) = 9.5.