A four-character code that identifies a telecommunications company in industry databases and is required to obtain STIR/SHAKEN credentials.
Operating Company Numbers are assigned by the National Exchange Carrier Association and identify a carrier in industry systems such as numbering, routing, and porting databases. A company can hold more than one OCN, for example to separate different service types or affiliates. OCNs appear in records such as the Local Exchange Routing Guide and are used by other carriers to identify who serves a given number block.
For STIR/SHAKEN, the OCN matters because the Service Provider Code in a provider's signing certificate is based on it. A provider without an OCN cannot obtain an SPC token from the Policy Administrator and therefore cannot get its own signing certificate. The Policy Administrator uses the OCN to confirm the identity of the applicant and to link its signing authority to a specific company.
Providers that do not hold numbering resources directly, such as many VoIP resellers, have increasingly obtained OCNs so they can sign calls in their own name rather than relying on an upstream carrier's signature. Signing under your own credentials also means your attestation decisions are attributed to you directly, which makes accurate onboarding and number records even more important.
Why it matters to carriers
If you plan to sign your own traffic, an OCN is a prerequisite, and FCC rules increasingly expect providers to authenticate calls with their own credentials. Keeping your OCN records, company name, and contacts consistent across NECA, the STI-PA, and your FCC filings avoids delays when tokens and certificates come up for renewal.