FAR 4.1601—Policy.
Plain-English Summary
FAR 4.1601 establishes the core policy for Procurement Instrument Identifiers (PIIDs), which are the unique numbers agencies use to identify solicitations and contract actions across the federal procurement system. It covers four main topics: the requirement to make each PIID unique Governmentwide for at least 20 years, the requirement to use the PIID in all solicitation and contract actions and in designated reporting/support systems such as FPDS and SAM, the transition from the older 2013 PIID format to the 2017 format using the agency identification code (AAC) in the first six positions, and the limited circumstances in which a PIID may be changed after assignment. In practice, this section is about data integrity, traceability, and consistency across procurement records, award systems, and reporting tools. It matters because a PIID is the primary identifier that ties together the solicitation, award, modifications, and downstream reporting, so errors can create compliance problems, reporting mismatches, and administrative confusion. The rule also protects historical records by requiring uniqueness for a long retention period and by limiting when a contracting officer may reassign a PIID. For contractors, the practical effect is that the identifier on the solicitation and award documents is not just a label; it is a controlled government record reference that must be used consistently throughout the life of the action.
Key Rules
PIIDs must be unique
Agencies must have a process that ensures every PIID used for a solicitation or contract action is unique Governmentwide and remains unique for at least 20 years from the date of contract award. This prevents duplicate identifiers across agencies and preserves traceability over time.
Use PIIDs everywhere required
The PIID must identify all solicitation and contract actions and must also be used in designated support and reporting systems, such as FPDS and SAM, consistent with applicable regulations, authorities, and agency procedures. In practice, the PIID is the common reference point across procurement records and reporting platforms.
Transition to the newer format
Agencies had to comply with the updated PIID requirements by October 1, 2017, for all new solicitations and contract awards. Until an agency completed its transition, it was required to keep using its 2013 PIID format on record with GSA’s Integrated Award Environment Program Office.
2013 and 2017 formats differ
The older 2013 format used alpha characters at the beginning to identify the agency, followed by alphanumeric characters. The 2017 format instead places the agency identification code (AAC) in the first six positions, standardizing the identifier structure.
PIIDs generally cannot change
Once assigned, a PIID may not be changed unless the serial numbering system is exhausted or continued use is administratively burdensome, such as when implementing a new contract writing system. In either case, the contracting officer may assign a new PIID only by issuing a contract modification.
Modifications must show both numbers
When a new PIID is assigned, the modification must clearly identify both the original PIID and the newly assigned PIID. The issuance of a new PIID is treated as an administrative change under FAR 43.101.
Responsibilities
Agencies
Establish and maintain a process that ensures PIIDs are unique Governmentwide for at least 20 years, use PIIDs in all solicitations and contract actions, and ensure PIIDs are used in designated reporting and support systems in accordance with applicable rules and agency procedures. Agencies also had to manage the transition from the 2013 PIID format to the 2017 format.
Contracting Officers
Assign PIIDs in accordance with the agency’s numbering process, avoid changing a PIID unless one of the limited exceptions applies, and issue a contract modification when a new PIID must be assigned. The contracting officer must also ensure the modification clearly shows both the old and new PIIDs.
Agency Procurement/Contract Writing Systems Owners
Configure and maintain systems so PIIDs are generated, recorded, and carried consistently across solicitation, award, modification, and reporting records. They must support the agency’s transition to the required PIID format and prevent duplicate or conflicting identifiers.
Reporting and Support System Administrators
Ensure that systems such as FPDS and SAM accept and display PIIDs consistently with the governing regulations, authorities, and agency policies. They must preserve the linkage between the PIID and the underlying procurement action.
Contractors
Use the PIID as the government-provided reference for the solicitation or contract action when communicating with the Government, submitting records, or reconciling award information. Contractors should verify that the PIID on award documents and related correspondence matches the official government record.
Practical Implications
PIID accuracy is critical because it ties together the solicitation, award, modifications, and reporting records; a mismatch can create data integrity problems and delay administration.
A PIID should not be treated like a casual file number. Once assigned, it is generally fixed, and changing it requires a formal modification and a valid reason under the rule.
Agencies that still have legacy numbering practices must ensure their systems and records align with the required format and with the agency’s registered identifier scheme.
When a new PIID is issued, both the old and new identifiers must be preserved in the modification to avoid breaking the audit trail.
Contractors should check that the PIID used in invoices, correspondence, and system submissions matches the award record, especially after a modification or system migration.
Official Regulatory Text
(a) Establishment of a Procurement Instrument Identifier (PIID). Agencies shall have in place a process that ensures that each PIID used to identify a solicitation or contract action is unique Governmentwide, and will remain so for at least 20 years from the date of contract award. The PIID shall be used to identify all solicitation and contract actions. The PIID shall also be used to identify solicitation and contract actions in designated support and reporting systems (e.g., Federal Procurement Data System, System for Award Management), in accordance with regulations, applicable authorities, and agency policies and procedures.) (b) Transition of PIID numbering. No later than October 1, 2017, agencies shall comply with paragraph (a) of this section and use the requirements in 4.1602 and 4.1603 for all new solicitations and contract awards. Until an agency’s transition is complete, it shall maintain its 2013 PIID format that is on record with the General Services Administration’s Integrated Award Environment Program Office (which maintains a registry of the agency unique identifier scheme). The 2013 PIID format consisted of alpha characters in the first positions to indicate the agency, followed by alpha-numeric characters; the 2017 format instead has the AAC in the beginning 6 positions. (c) Change in the Procurement Instrument Identifier after its assignment. (1) Agencies shall not change the PIID unless one of the following two circumstances apply: (i) The PIID serial numbering system is exhausted. In this instance, the contracting officer may assign a new PIID by issuing a contract modification. (ii) Continued use of a PIID is administratively burdensome (e.g., for implementations of new agency contract writing systems). In this instance, the contracting officer may assign a new PIID by issuing a contract modification. (2) The modification shall clearly identify both the original and the newly assigned PIID. Issuance of a new PIID is an administrative change (see 43.101 ).