  Multi-trace scalar operators in the (0,k,0) representations of SU(4)_R share
many properties with their single-trace analogs. These multi-trace operators
are primary fields of short representations of the N=4 superconformal group.
Thus, they have protected dimensions. We show that two- and three-point
correlator functions of such operators do not receive radiative corrections at
order g^2 in perturbation theory for an arbitrary gauge group.
