Extreme Primordial Black Holes
  We present a formalism for calculating the probability distribution of the
most massive primordial black holes (PBHs) expected within an observational
volume. We show how current observational upper bounds on the fraction of PBHs
in dark matter translate to constraints on extreme masses of primordial black
holes. We demonstrate the power of our formalism via a case study, and argue
that our formalism can be used to produce extreme-value distributions for a
wide range of PBH formation theories.
