Galaxy stellar mass versus halo virial mass relation. Bottom axes indicate M₂₀₀ in M_⊙; top axes indicate virial velocity, V₂₀₀, in km s⁻¹. The left-hand panel corresponds to EAGLE, right-hand panel to TNG. Symbols show individual galaxies coloured by morphology: red circles indicate early-type (E); blue spiral symbols denote late-type (S); and grey squares are used for all others. Solid and dashed thick black curves indicate, for reference, the results of abundance-matching models from Behroozi et al. (2019) and Moster et al. (2018), respectively. Open symbols (diamonds for EAGLE, triangles for TNG) indicate median M₂₀₀ values in the four bins of M_* highlighted by the grey horizontal bands (these are used for the model curves shown in Fig. 3). ‘Error bars’ in each symbol denotes the 25–75 percentile range in each bin. Starred coloured symbols correspond to halo masses used for the models discussed in Fig. 9.