# DUNS and Commercial Credit Identity

## Source Type

Industry registry. Dun & Bradstreet Data Universal Numbering System (D-U-N-S).

## Domain

Commercial credit, vendor onboarding, procurement identity, and business verification.

## Why This Source Matters

DUNS predates LEI as a global commercial identifier for **business entities** in
trade and credit. It ties identity to **creditworthiness and payment behavior**
(PAYDEX), illustrating how commercial activity creates durable, high-stakes identity
interest among counterparties.

## Key Concepts

- **DUNS number**: nine-digit proprietary identifier for a business location/entity.
- **D&B database**: 300M+ business records; global trade and procurement usage.
- **Business entity**: company or location receiving DUNS; not a natural person.
- **PAYDEX score**: D&B payment performance score (credit behavior).
- **Credit file**: aggregated commercial history attributed to DUNS.
- **Government procurement**: historically required DUNS (US); migrated to SAM UEI.
- **UEI (Unique Entity Identifier)**: US federal successor identifier in SAM.gov.
- **ISO/IEC 6523 ICD 0060**: standard representation for DUNS in ISO identifiers.

## Relevant Terminology

| Term | Source meaning |
| --- | --- |
| DUNS / D-U-N-S | D&B business identifier. |
| Business entity | Company or site in D&B registry. |
| PAYDEX | Payment performance score. |
| Credit file | Commercial history record. |
| UEI | US government unique entity ID (SAM.gov). |
| Vendor onboarding | Procurement verification using DUNS/UEI. |
| Headquarters vs. branch | Separate DUNS per distinct business location. |

## Modeling Assumptions

- **Commercial identity serves credit and procurement**, not authentication.
- **Payment history feeds reputation** attributable to identifier.
- **Multiple national ID schemes** (DUNS, UEI, LEI, VAT, company reg) coexist; linking
  requires Synonymity Assertion or registry crosswalk.
- **Identifier assignment is vendor-operated** (D&B), not self-asserted.
- **Commercial counterparties rely on DUNS** for risk decisions beyond bare legal existence.

## Identity-Canon Implications

- DUNS maps to **Proxy Commercial Identifier** (`scheme: 0060`,
  `authority_class: commercial_proxy`) on **Commercial Record** / **Organization**.
- PAYDEX and credit file map to **Evidence Source** influencing **Trust Relationship**
  and counterparty risk.
- UEI maps to **Identifier** (government authoritative) on Commercial Record.
- Illustrates user thesis: once credit exposure exists, identity becomes **economically
  binding** and **reputationally persistent**.
- Link to LEI via Synonymity Assertion when same legal entity holds both.

## Terminology Conflicts

- **DUNS** vs. **LEI**: credit/procurement vs. financial regulatory identifier.
- **Business entity (D&B)** vs. **Tenant**: vendor record ≠ SaaS isolation.
- **Customer (credit)** vs. **Customer (role)**: credit customer vs. relationship role.

## Candidate Canonical Mappings

| D&B / procurement concept | Candidate canonical concept |
| --- | --- |
| DUNS number | Proxy Commercial Identifier (ICD 0060) |
| D&B business record | Commercial Record |
| PAYDEX | Evidence Source (credit performance) |
| UEI | Identifier (government registry) |
| Vendor onboarding check | Trust Relationship + Evidence Source |
| Parent/branch linkage | Organization structure Relationship |

## Open Questions

*(none — settled in `commercial-identity-nuance-settlement.md`)*

## Settled

- PAYDEX → Performance Evidence; `numeric_score` optional; tier enum primary.
- LEI↔DUNS Synonymity default **medium**.

## References

- Dun & Bradstreet DUNS — https://www.dnb.com/duns-number.html
- Wikipedia, Data Universal Numbering System — https://en.wikipedia.org/wiki/Data_Universal_Numbering_System
- GSA Unique Entity Identifier — https://www.gsa.gov/about-us/organization/federal-acquisition-service/fas-initiatives/integrated-award-environment/iae-systems-information-kit/unique-entity-identifier-update