  The bosonic sector of various supergravity theories reduces to a homogeneous
space G/H in three dimensions. The corresponding algebras g are simple for
(half-)maximal supergravity, but can be semi-simple for other theories. We
extend the existing literature on the Kac-Moody extensions of simple Lie
algebras to the semi-simple case. Furthermore, we argue that for N=2
supergravity the simple algebras have to be augmented with an su(2) factor.
