The authors study the universal enveloping algebra \(U\) of the loop extension (over the field \(C((z))\)) of a semi-simple finite dimensional Lie algebra \(g\). There is a standard filtration \(U_k\) on \(U\) and under these conditions there is another filtration defined by the powers of the maximal ideal \(m\) in \(C[[z]]\). Namely, let \(I_{n,k} = \)(left ideal, generated by \(g \otimes m^n) \cap U_k\). The main result is a canonical isomorphism between \(U/I_{n,k}\) and some space of symmetric differential forms attached to the ring \(C[[z_1, \dots, z_r]]\) for \(r < k + 1\).