  We consider supergravity theories with 16 supercharges in Minkowski space
with dimensions $d>3$. We argue that there is an upper bound on the number of
massless modes in such theories depending on $d$. In particular we show that
the rank of the gauge symmetry group $G$ in $d$ dimensions is bounded by
$r_G\leq 26-d$. This in particular demonstrates that 4 dimensional ${\cal N}=4$
SYM theories with rank bigger than 22, despite being consistent and indeed
finite before coupling to gravity, cannot be consistently coupled to ${\cal
N}=4$ supergravity in Minkowski space and belong to the swampland. Our argument
is based on the swampland conditions of completeness of spectrum of defects as
well as a strong form of the distance conjecture and relies on unitarity as
well as supersymmetry of the worldsheet theory of BPS strings. The results are
compatible with known string constructions and provide further evidence for the
string lamppost principle (SLP): that string theory lamppost seems to capture
${\it all}$ consistent quantum gravitational theories.
