Distribution of the percentage difference between the stellar masses from Subfind and $2\times R_{M_{\mathrm{star}}/2}\sim r_{\mathrm{op}}$ apertures under different constrains. The black, red, and blue lines correspond to measurements within halocentric radius R_500c, R_200c, and the mass considered by the FoF algorithm, respectively. The dashed lines represent the normal distribution fitted to each constraint and are shown in their corresponding colour.