Stellar galaxy masses plotted against the SALT2 x₁ parameter for the good light-curve coverage sample of the volume-limited sample of ZTF DR 2 SN Ia (1106 SNe Ia, including the six hostless SNe Ia). A relative percentage of sub-types in each mass bin is plotted as a histogram above the figure and the cumulative occurrence of these types is illustrated as additive. The distribution of the sub-type normal is excluded where it is mostly constant in each mass bin with a range of (65−77%). Different colours of circles, represent different sub-types used in this study. For the selection of sub-type methods, we refer to Sect. 3.2. The gray and black dashed line represents the separation for the low, intermediate, and high stellar galaxy masses.