  Recent observations with JWST have identified several bright galaxy
candidates at $z\gtrsim 10$, some of which appear unusually massive (up to
$\sim 10^{11}\ \rm M_{\odot}$). Such early formation of massive galaxies is
difficult to reconcile with standard $\Lambda\rm CDM$ predictions, demanding
very high star formation efficiency (SFE), possibly even in excess of the
cosmic baryon mass budget in collapsed structures. With an idealized analysis
based on linear perturbation theory and the Press-Schechter formalism, we show
that the observed massive galaxy candidates can be explained with lower SFE
than required in $\Lambda\rm CDM$, if structure formation is accelerated/seeded
by massive ($\gtrsim 10^{9}\ \rm M_{\odot}$) primordial black holes (PBHs) that
make a up a small fraction ($\sim 10^{-6}-10^{-3}$) of dark matter, considering
existing empirical constraints on PBH parameters. We also discuss the potential
observational signatures of PBH cosmologies in the JWST era. More work needs to
be done to fully evaluate the viability of such PBH models to explain
observations of the high-$z$ Universe.
