Not a parallel state - a network of voluntarily-associating actors. The State is coercive and monopolistic, a voluntary network is Exit-preserving.
You don't "regulate" the parallel economy, because it doesn't consent to being regulated, and it (if functioning correctly) will avoid all of your attempts to regulate it. Rather, its actors agree to various norms amongst each other. A "self-regulating" patchwork, in a sense.
