How do you distribute more than is owed yet call it a ‘bankruptcy’?
I believe they converted shareholder and creditors money to private (their own) use. The bankruptcy referee was able to "claw back" the funds. Madoff + his wife + his sons own assets were worth about 10% of the "investors" accounts. There was some luck in that one of his friends who made about seven billion from his "investments" left an estate worth about twice that. His widow turned over the seven billion, from about ten years before the bankruptcy without hesitation.