  It is argued that recent developments point to the existence of an AdS_3 x
S^2 x T^5 holographic dual for the 2D CFT living on the worldsheet of N
coincident heterotic strings in a T^5 compactification, which can in turn be
described by an exact worldsheet CFT. A supergravity analysis is shown to imply
that the global supergroup is Osp(4^*|4), with 16 supercharges and an affine
extension given, surprisingly, by a nonlinear N=8 2D superconformal algebra.
Possible supergroups with 16 supercharges are also found to match the expected
symmetries for T^n compactification with 0<=n<=7.
