  In this paper, we show that the initial clustering of supermassive primordial
black holes (SMPBHs) beyond a Poisson distribution can efficiently enhance the
matter power spectrum, and thus the halo mass function. As a result, the
population of initially clustered SMPBHs with $M_{\rm PBH}\sim 10^9M_\odot$ and
the fraction of energy density $f_{\rm PBH}\sim 10^{-3}$ (consistent with
current constraints on SMPBHs) has the potential to naturally explain
high-redshift massive galaxies observed by the James Webb Space Telescope.
