  We consider the ${\cal N}=4$ Liouville theory by varying the linear dilaton
coupling constant $\cal{Q}$. It is known that at two different values of
coupling constant ${\cal Q}=\sqrt{{2\over N}},-(N-1)\sqrt{{2\over N}}$ system
exhibits two different small ${\cal N}=4$ superconformal symmetries with
central charge $c=6$ and $c=6(N-1)$, respectively. In the context of string
theory these two theories are considered to describe Coulumb and Higgs branch
of the theory and expected to be dual to each other. We study the Mathieu and
umbral moonshine phenomena in these two theories and discuss their dual
description. We mainly consider the case of $A_N$ type modular invariants.
