20 C.F.R. § 422.846
(b) Bases for compromise—(1) Compromise. We may compromise a debt if the agency cannot collect the full amount based upon the debtor's inability to pay, inability to collect the full debt, the cost of collection, or if we are doubtful that the debt can be proven in court.
(i) Inability to pay. We may compromise a debt if the debtor is unable to pay the full amount in a reasonable time, as verified through credit reports or other financial information. In determining a debtor's inability to pay the full amount of the debt within a reasonable time, we will obtain and verify the debtor's claim of inability to pay by using credit reports and/or a current financial statement from the debtor, executed under penalty of perjury, showing the debtor's assets, liabilities, income, and expenses. We may use a financial information form used in connection with the agency's programs or may request suitable forms from the DOJ or the local United States Attorney's Office. We also may consider other relevant factors such as:
(ii) Inability to collect full debt. We may compromise a debt if the Government is unable to collect the debt in full within a reasonable time by enforced collection proceedings.
(iii) Cost of collection. We may compromise a debt if the cost of collecting the debt does not justify the enforced collection of the full amount.
(iv) Doubtful debt can be proven in court. We may compromise a debt if there is significant doubt concerning the Government's ability to prove its case in court.
(d) Joint and several liability.