Impact of the simulation box size L on the mass variance (top panel) and the differential HMF (bottom panel) for three different cases L = {500, 1000, 2000} h⁻¹ Mpc depicted in red, blue, and green, respectively. Solid lines represent the mean effect due to the truncation of the mass variance integration to the fundamental mode. The corresponding shaded regions correspond to the 68 percent interval due to the sample variance.