You can't legitimately regulate a Ponzi scheme. You can only shut it down, arrest the perpetrators, recover the gains from those that profited, and distribute those gains to the losers for pennies on the dollar.

Like they did with Madoff and the "investors" who made money off the Ponzi scheme. To avoid going to prison as de facto accomplices (they couldn't prove they didn't know it was a scam), they returned all of their gains to a common pool.