GROND g′, r′, i′, and z′ absolute magnitude light curves of SN 2018bsz (Chen et al. 2021) in comparison to the integrated luminosity of the blue Hα component (BC). The blue component becomes fainter simultaneously with the light curve at ∼100 d. The Hα luminosities were estimated based on the Gaussian fits described in Sect. 3.2. At 121.3 d no emission component was seen and the stated value is a 2σ upper limit for the non-detection shown with a downward triangle. Note that the axis scales are set so that 2.5 mag = 1Log(L).