Evolution of the black hole–to–stellar mass ratio. Top: log(M_BH/M_⋆) versus redshift for the three AGN populations in this study, with high-redshift AGNs (z > 4) from the literature shown for comparison. Bottom: log(M_BH/M_⋆) versus stellar mass, including high-redshift dwarf AGNs (Sun et al. 2025b) and X-ray AGNs from the XXL and 4XMM surveys. Dashed lines show linear fits to the binned data; for XXL AGNs, the fit is limited to log(M_⋆/M_⊙) < 11. Solid and dashed horizontal lines indicate the average ratio for XMM-XXL AGNs at z < 2 (Mountrichas 2023) and for local inactive galaxies, respectively.