49 C.F.R. § 1018.70 – Prompt referral.

(a) A claim which requires enforced collection is referred to GAO or DOJ for litigation. A referral is made as early as possible consistent with aggressive collection action and, in, any event, well within the time required to bring a timely suit against the debtor. Ordinarily, referrals are made within 1 year of the Board's final determination of the fact and the amount of the debt.
(b) When the merits of the Board's claim, the amount owed on the claim, or the propriety of acceptance of a proposed compromise, suspension, or termination of collection actions is in doubt, the Board shall refer the matter to GAO for resolution and instruction prior to proceeding with collection actions and/or referral to DOJ for litigation.
(c) The Board may refer a claim to GAO or DOJ even though the termination of collection activity might otherwise be given consideration under § 1018.63 if:
1. (1) A significant enforcement policy is involved in reducing a statutory penalty or forfeiture to judgment; or
2. (2) Recovery of a judgment is a prerequisite to the imposition of administrative sanctions, such as suspension or revocation of a license or privilege of participating in a Government sponsored program.
(d) Once a claim has been referred to GAO or DOJ under this subpart, the Board shall refrain from any contact with the debtor and shall direct the debtor to GAO or DOJ as appropriate, when questions concerning the claim are raised by the debtor. The Board shall immediately advise GAO or DOJ, as appropriate, of any payments by the debtor.