Mass-radius diagram of all rocky USPs (R_p < 2R_⊕, P < 1 day) around M dwarfs (T_eff < 4000 K) and FGK stars that currently have a measured mass and radius. All planet parameters were obtained through a query search on NASA Exoplanet Archive. Silicate-rich (blue), Earthlike (green), and iron-rich (orange) composition lines, taken from Zeng et al. (2019), are overplotted. According to the measured mass and radius, TOI-4552 b lies in the gap between the Earth-like and pure iron composition lines. A more precise mass measurement is required to obtain better constraints on the composition.