Del. Code tit. 29 § 6984
In the case of any contract entered into by an agency other than any county of this State and other than a public school district, and which is not excluded under §§ 6980 and/or 6981 of this title, no contract shall be executed unless and until the firm has provided the agency with its taxpayer identification number (i.e., federal employer identification number or social security number) or its Delaware business license number and, within 15 days of the time identification of any subcontractor shall be required or at the time the contract is executed, whichever is later, the number of such subcontractor. The agency shall report to the Division of Revenue each firm and subcontractor selected for an award within 15 days of identification of such firm or subcontractor under this section unless the Director of the Division of Revenue notifies the agency of criteria according to which, in the Director's discretion, reporting is not required, and the contract meets such criteria.
29 Del. C. § 6984