Distribution of stellar masses. Shown are the FFB predictions for the number density of galaxies with stellar masses above 10⁹ M_⊙ (left panel) or 10¹⁰ M_⊙ (right panel). The blue and orange lines refer to ϵ_max​ = ​1 and 0.2, respectively. The standard UM model (B19) is shown for comparison (gray line). The FFB predictions are above the UM model for z​ ≥ ​6, and more so at higher redshifts. Shown for tentative comparison are the observational measurements compiled by Chworowsky et al. (2023), including JWST data (Labbé et al. 2023; Chworowsky et al. 2023) as well as earlier HST data (Song et al. 2016; Stefanon et al. 2021; Weaver et al. 2023). The JWST measurements are systematically higher than the previous measurements and they are above the standard UM model. The observations seem to favor the FFB prediction with ϵ_max​ ≳ ​0.2.