Light curves of four (three complete and one partial) transits of HATS-2 b simultaneously observed in four optical bands (Sloan g′, r′, i′, z′) with the GROND multi-band camera at the MPG 2.2 m telescope. They are shown in date order. The light curves in the top panels are from Mohler-Fischer et al. (2013), while those in the bottom panels are from this work. Starspot anomalies are visible in the first three data sets. The light curves are plotted against the orbital phase and are compared to the best-fitting models. The residuals of the fits are shown at the base of each panel.