5 CFR §890.1012

1. (a)Licensure cases. If the basis for the proposed debarment is a licensure action, OPM shall send the provider a notice of proposed debarment within 6 years of the effective date of the State licensing authority's revocation, suspension, restriction, or nonrenewal action, or the date on which the provider surrendered his license to the State authority.
2. (b)Ownership or control. If the basis for the proposed debarment is ownership or control of an entity by a sanctioned person, or ownership or control of a sanctioned entity by a person who knew or should have known of the basis for the entity's sanction, OPM shall send a notice of proposed debarment within 6 years of the effective date of the sanction on which the proposed debarment is based.
3. (c)False, deceptive, or wrongful claims practices. If the basis for the proposed debarment involves a claim filed with a FEHBP carrier, OPM shall send the provider a notice of proposed debarment within 6 years of the date he presented the claim for payment to the covered person's FEHBP carrier.
4. (d)Failure to furnish requested information. If the basis for the proposed debarment involves a provider's failure to furnish information requested by OPM or an FEHBP carrier, OPM shall send the notice of proposed debarment within 6 years of the date on which the carrier or OPM requested the provider to furnish the information in question.