Combining constraints from microlensing and Lyman-$\alpha$ forest, we provide a simple argument to show that large spatial clustering of stellar-mass primordial black holes at the time of formation, such as the one induced by the presence of large non-Gaussianities, is ruled out. Therefore, it is not possible to evade existing constraints preventing stellar-mass primordial black holes from being a dominant constituent of the dark matter by boosting their initial clustering.

• Received 8 August 2022
• Revised 4 October 2022
• Accepted 14 October 2022

DOI:https://doi.org/10.1103/PhysRevLett.129.191302