13 CFR §121.505

1. (a)A contracting officer may accept a concern's self-certification as true for the particular sale or lease involved, in the absence of a written protest by other offerors or other credible information which would cause the contracting officer or SBA to question the size of the concern.
2. (b)Procedures for protesting the self-certification of an offeror are set forth in §§ 121.1001 through 121.1009.