Net Delivery Obligations (NDO) refer to the net amount owed to settle all active and outstanding obligations. It is the summation of:
NDO = Payable + Collateral Payable - Available - Collateral - Receivable
For example, assume a participant has $100,000 USD in their Available account and $60,000 collateral for an open position. They owe $200k to fully close out the position. Their Net Delivery Obligation would equal:
NDO = $200,000 + $0 - $100,000 - $60,000 - $0
NDO = $40,000
Once the participant deposits $40,000, their position will fully settle.