  We study the impact on electroweak baryogenesis from a swifter cosmological
expansion induced by dark matter. We detail the experimental bounds that one
can place on models that realize it, and we investigate the modifications of
these bounds that result from a non-standard cosmological history. The
modifications can be sizeable if the expansion rate of the Universe increases
by several orders of magnitude. We illustrate the impact through the example of
scalar field dark matter, which can alter the cosmological history enough to
enable a strong-enough first-order phase transition in the Standard Model when
it is supplemented by a dimension six operator directly modifying the Higgs
boson potential. We show that due to the modified cosmological history,
electroweak baryogenesis can be realized, while keeping deviations of the
triple Higgs coupling below HL-LHC sensitivies. The required scale of new
physics to effectuate a strong-enough first order phase transition can change
by as much as twenty percent as the expansion rate increases by six orders of
magnitude.
