11 U.S.C. § 751: Customer name securities

The trustee shall deliver any customer name security to or on behalf of the customer entitled to such security, unless such customer has a negative net equity. With the approval of the trustee, a customer may reclaim a customer name security after payment to the trustee, within such period as the trustee allows, of any claim of the debtor against such customer to the extent that such customer will not have a negative net equity after such payment.