29 C.F.R. § 100.604

The NLRB's authority to compromise a debt or to suspend or terminate collection action on a debt covered by these procedures is limited by 31 U.S.C. 3711(a) to claims that:

(a) Have not been referred to another Federal Agency for further collection actions; and

(b) Do not exceed $100,000 (exclusive of any interest) or such higher amount as the Attorney General shall from time to time prescribe for purposes of compromise or suspension or termination of collection activity.