  The final mass distribution of primordial black holes is sensitive to the
equation of state of the Universe at the scales accessible by the power
spectrum. Motivated by the presence of phase transitions in several beyond the
Standard Model theories, some of which are strongly coupled, we analyze the
production of primordial black holes during such phase transitions, which we
model using the gauge/gravity duality. We focus in the (often regarded as
physically uninteresting) case for which the phase transition is just a smooth
crossover. We find an enhancement of primordial black hole production in the
range $M_{\rm{PBH}}\in[10^{-16},10^{-6}]M_{\odot}$.
