  The IKKT matrix model was proposed to be a non-perturbative formulation of
type IIB superstring theory. One of its important consistency criteria is that
the leading one-loop $1/r^8$ effective interaction between a cluster of type
IIB D-objects should not receive any corrections from higher loop effects for
it to describe accurately the type IIB supergravity results. In analogy with
the BFSS matrix model {\it versus} the eleven-dimensional supergravity example,
we show in this work that the one-loop effective potential in the IKKT matrix
model is also not renormalized at the two-loop order.
