On any Settlement Day, the Clearing Bank shall be liable, as principal and primary obligor, to pay to CDP the Net-Net Debit Balance or any shortfall in the Net-Net Debit Balance of any Settlement Bank who has defaulted in its payment obligations to CDP pursuant to Rule 8.3.4. Subject to Rule 13.3, the Net-Net Debit Balance of any Settlement Bank shall not exceed its SB Net Debit Cap.