HIMF from the combined stacking (blue squares), MIGHTEE stacking (orange diamonds), and CHILES stacking (green circles). Top: HIMF results adopting the linear model for the M_HI − M_⋆ scaling relation. Bottom: HIMF results adopting the polynomial model for the M_HI − M_⋆ scaling relation. We also show the best-fitting Schechter models as solid blue, dashed orange, and dotted-dashed green lines, respectively. The ALFALFA HIMF at z ∼ 0 (dashed purple) is shown for comparison.