  The Weak Gravity Conjecture (WGC) in anti-de Sitter spacetime (AdS) asserts
the existence of an operator in the boundary conformal field theory (CFT) whose
scaling dimension-to-charge ratio satisfies a certain upper bound. This bound
is specified by the ratio of the conformal central charge $c$ and the flavor
central charge $k_F$. We propose a modified bound in AdS5/CFT4, determined by a
combination of two central charges $3c-2a$ instead of $c$. This combination
arises in the Cardy-like limit of the 4d superconformal index, which captures
the Bekenstein-Hawking entropy of large BPS black holes in AdS5. Using the new
bound, we find that certain superconformal field theories (SCFTs) that are
previously thought to violate the AdS WGC, including SQCDs in the conformal
window, do satisfy the WGC. We check this version of the WGC against all
possible superconformal gauge theories with SU(N) gauge group admitting a large
N limit when the superpotential is absent. We conjecture the modified version
of the WGC is a generic property of any 4d SCFT, regardless of the existence of
a weakly coupled gravity dual or a large N limit.
