49 CFR 1018.80: Reporting discharged debts to the Internal Revenue Service.

When the Board discharges a debt for less than the full value of the indebtedness, it will report the outstanding balance discharged, not including interest to the Internal Revenue Service, using IRS Form 1099-G or any other form prescribed by the IRS, when:

(a) The principal amount of the debt not in dispute is $600 or more;

(b) The obligation has not been discharged in a bankruptcy proceeding; and

(c) The obligation is no longer collectible either because the time limit in the applicable statute for enforcing collection expired during the tax year, or because during the tax year a formal compromise agreement was reached in which the debtor was legally discharged of all or a portion of the obligation.