  I investigate the possibility that the observed curvature perturbation is due
to a massive vector field. To avoid generating a large scale anisotropy the
vector field is not taken to be driving inflation. Instead it is assumed to
become important after inflation when it may dominate the Universe and imprint
its perturbation spectrum before its decay, as in the curvaton scenario. It is
found that, to generate a scale invariant spectrum of perturbations, the
mass-squared of the vector field has to be negative and comparable to the
Hubble scale during inflation. After inflation the mass-squared must become
positive so that the vector field engages into oscillations. It is shown that,
such an oscillating vector field behaves as pressureless matter and does not
lead to large scale anisotropy when it dominates the Universe. The possibilitiy
of realising this scenario in supergravity is also outlined.
