376.220—What contracts and subcontracts, in addition to those listed in 2 CFR 180.220, are covered transactions?
         In addition to the contracts covered under  2 CFR 180.220(b), this part also applies to all lower tiers of subcontracts under covered nonprocurement transactions, as permitted under the OMB guidance at  2 CFR 180.220(c). (See optional lower tier coverage in the diagram in the appendix to  2 CFR part 180.)