Star formation efficiency adopted for the FFB model, as in Fig. 1, but via curves of SFE versus M_v for a given z (left) and SFE versus z for a given M_v (right). The SFE is made to coincide with the standard UM model (B19) (dashed lines) at low masses and redshifts and to approach ϵ_max above the FFB thresholds of mass and redshift. The shaded areas refer to a maximum SFE that ranges from ϵ_max​ = ​0.2 (bottom) to 1 (top). The FFB threshold is at roughly 0.5 ϵ_max. The SFE does not reach ϵ_max for M_v​ ≥ ​10^12.5 M_⊙ where SFR quenching is assumed.