  Analysis of the statistical properties of exoplanets, together with those of
their host stars, are providing a unique view into the process of planet
formation and evolution. In this paper we explore the properties of the mass
distribution of giant planet companions to solar-type stars, in a quest for
clues about their formation process. With this goal in mind we studied, with
the help of standard statistical tests, the mass distribution of giant planets
using data from the exoplanet.eu catalog and the SWEET-Cat database of stellar
parameters for stars with planets. We show that the mass distribution of giant
planet companions is likely to present more than one population with a change
in regime around 4\,M$_{Jup}$. Above this value host stars tend to be more
metal poor and more massive and have [Fe/H] distributions that are
statistically similar to those observed in field stars of similar mass. On the
other hand, stars that host planets below this limit show the well-known
metallicity-giant planet frequency correlation. We discuss these results in
light of various planet formation models and explore the implications they may
have on our understanding of the formation of giant planets. In particular, we
discuss the possibility that the existence of two separate populations of giant
planets indicates that two different processes of formation are at play.
