Bank-Entity Identifier Systems Guide¶

The definitive guide to the identifier systems that link US bank datasets together — RSSD ID, FDIC Certificate, OCC Charter, NCUA Charter/ID, LEI, ABA Routing Number, OTS Docket/Thrift ID, EIN/Tax ID, CIK, and CUSIP/ticker. For each identifier this guide gives the issuer, format, scope, persistence/reuse rule, and the datasets that key on it; the Crosswalk section then explains how the identifiers map to one another and the hazards of joining across sources.

All facts below are drawn from official sources (.gov, gleif.org, sec.gov) and from the FFIEC NPW Data Dictionary (Board of Governors of the Federal Reserve System, Bulk Data Download — Data Dictionary and Reference Guide, Document Version 2.0, Rev. 4/25, prepared by the National Information Center). Items that could not be verified against an official source are marked UNVERIFIED.

For the institutional-structure data (NIC/NPW Attributes / Relationships / Transformations tables, ownership graph, merger lineage), see docs/NIC_STRUCTURE_GUIDE.md.

Last compiled: 2026-06-09.

1. Identifier Reference¶

1.1 RSSD ID¶

Also known as: ID_RSSD, RSSD9001, the "NIC" id.
Issuer: Federal Reserve Board — Research, Statistics, Supervision & Regulation, and Discount & Credit database / National Information Center (NIC).
Format: Sequential integer (1, 2, 3, …) with a check digit, assigned by the RSSD software at first entry; no fixed length. Carries no inherent attribute information.
Scope: Every entity the Fed tracks — banks, BHCs/FHCs, branches, savings institutions, holding-company tiers, and some foreign and non-bank entities.
Persistence / reuse rule: Stable for the life of the entity. Never changes, never reused. Each entity has one and only one RSSD ID for its entire life cycle; it persists after liquidation or closure. The legal name can change while the RSSD ID stays fixed. New entities receive the next integer.
Datasets that key on it: NIC/NPW (master key), FFIEC Call Reports / FFIEC 031/041 (RSSD9001), FR Y-9C and the entire FR Y-series, FFIEC CDR, FRED bank series, and most academic bank panels.
Why it matters: Because it never changes and never recycles, the RSSD ID is the most stable join key across charter changes and over time — the canonical spine for linking institutional structure to financial data.

1.2 FDIC Certificate Number¶

Also known as: CERT, FDIC Cert ID, FED_CERT; ID_FDIC_CERT in NIC.
Issuer: Federal Deposit Insurance Corporation.
Format: Sequential integer (no check digits).
Scope: Every FDIC-insured depository institution (banks and savings institutions). Assigned per head-office depository.
Persistence / reuse rule: Unique per insured institution; assigned at insurance and retained through the institution's life; not recycled in practice. As a sequential-integer system it is not globally unique without an agency qualifier (see Crosswalk §2).
Datasets that key on it: FDIC BankFind / SDI (Statistics on Depository Institutions) / Summary of Deposits / failures lists; pre-2018 HMDA respondent id (agency code 3). FDIC records also carry the RSSD as FED_RSSD.

1.3 OCC Charter Number¶

Issuer: Office of the Comptroller of the Currency.
Format: Sequential integer. (ID_OCC in NIC.)
Scope: National banks and — since July 21, 2011 — federal savings associations / federal thrifts.
Persistence / reuse rule: Assigned at chartering and retained through the institution's life. Beginning July 21, 2011 the OCC absorbed OTS thrift supervision; the OCC Charter field now also stores national thrifts as thrift docket + 700,000.
Datasets that key on it: OCC chartering data; pre-2018 HMDA respondent id (agency code 1). Carried as an attribute on the NIC RSSD record.

1.4 NCUA Charter / ID Number¶

Issuer: National Credit Union Administration.
Format: Sequential integer. (ID_NCUA in NIC.) Banded by insurance/charter type: 1–59,999 = Federal; 60,000–79,999 = Federally Insured, State Chartered; 80,000+ = Non-Federally Insured.
Scope: Federally insured credit unions (and some non-federally-insured).
Persistence / reuse rule: Assigned at chartering and retained through life. Sequential-integer system.
Datasets that key on it: NCUA Call Report / Research-a-Credit-Union; pre-2018 HMDA respondent id (agency code 5).

1.5 LEI (Legal Entity Identifier, ISO 17442)¶

Issuer: GLEIF governs; codes are issued by accredited Local Operating Units (LOUs), overseen by the LEI Regulatory Oversight Committee (ROC).
Format: 20-character alphanumeric — chars 1–4 = LOU prefix, chars 5–18 = entity-unique string, chars 19–20 = MOD-97-10 checksum (ISO/IEC 7064). (ID_LEI in NIC.)
Scope: Any legal entity participating in financial transactions, globally.
Persistence / reuse rule: Permanently unique to one entity; never reused. Must be renewed annually to keep an "issued/active" registration status, but the code itself persists regardless.
Datasets that key on it: HMDA filer id (2018-forward), SEC/CFTC swap reporting, FR Y-series LEI fields, and the GLEIF golden-copy file.
Coverage caveat: LEIs exist only from ~2012 forward and only for entities that obtained one; they cannot back-fill pre-2012 panels (see Crosswalk §2).

1.6 ABA Routing Transit Number (RTN)¶

Issuer: American Bankers Association via its registrar (currently LexisNexis Risk Solutions; historically Accuity / Thomson Financial), in coordination with the FRB district. (ID_ABA_PRIM in NIC.)
Format: 9 digits, FFFF AAAA C — Fed routing symbol (4) + ABA institution id (4) + MOD-10 check digit (1).
Scope: Financial institutions eligible for a Federal Reserve master account; identifies a payment-routing account, not the legal entity.
Persistence / reuse rule: Tied to payment routing, not entity identity. Reassignable / retirable after mergers, and reusable across non-concurrent entities (no two concurrent entities share one). One institution may hold many RTNs.
Datasets that key on it: Fedwire/ACH routing files, FedACH, the E-Payments Routing Directory.
Why it matters: An RTN is not an entity key — never use one as a persistent entity identifier (see Crosswalk §2).

1.7 OTS Docket Number / Thrift ID¶

Issuer: (former) Office of Thrift Supervision — defunct since July 21, 2011. (ID_THRIFT in NIC; the related ID_THRIFT_HC is the OTS-assigned "H"+5-digit holding-company id for owners of S&Ls / federal savings banks.)
Format: Numeric docket. The NIC ID_THRIFT field is 9 characters but only the right-most 5 are used; populated for charter types 300/310 that are FHLB members.
Scope: Savings institutions / thrifts (legacy).
Persistence / reuse rule: Legacy identifier. OTS functions transferred to OCC/FDIC/Fed under Dodd-Frank; new thrift supervision uses OCC Charter / RSSD.
Datasets that key on it: Legacy thrift datasets; historical TFR (Thrift Financial Report) data; pre-2018 HMDA agency code 4 (legacy).

1.8 Federal Tax ID / EIN¶

Issuer: Internal Revenue Service. (ID_TAX in NIC, effective 2008-12-31.)
Format: 9 digits, NN-NNNNNNN.
Scope: Any US entity with tax obligations.
Persistence / reuse rule: Permanently assigned to a legal entity; not recycled to another entity. Multiple entities under one parent each have their own EIN.
Datasets that key on it: Pre-2018 HMDA fallback respondent id; SEC filings. It is not a primary bank-regulatory key.

1.9 CIK (Central Index Key)¶

Issuer: SEC EDGAR.
Format: Integer, zero-padded to 10 digits in API paths (CIK##########).
Scope: Any EDGAR filer — companies (including public bank holding companies), funds, and individuals.
Persistence / reuse rule: Assigned at filer signup; unique to the filer and not recycled. Maps a filer to all of its filings.
Datasets that key on it: SEC EDGAR submissions / XBRL APIs and all SEC filings.
Linking caveat: CIK is independent of RSSD/CERT; joining public-BHC financials to regulatory data requires an external CIK↔RSSD crosswalk. The NIC/NPW Attributes table does carry an SEC reporting-status indicator (SEC_RPTG_STATUS, an integer code 0–5 keyed to §13(a)/15(d) of the Securities Exchange Act of 1934 and §404 of Sarbanes-Oxley), but it does not carry the CIK itself — there is no CIK column in NIC/NPW. No official SEC↔Fed CIK↔RSSD mapping is published by the SEC, FFIEC, or NIC, so the link is commonly built CIK → FDIC cert → RSSD.

1.10 CUSIP / Ticker¶

CUSIP issuer: CUSIP Global Services (operated for the American Bankers Association). (ID_CUSIP in NIC.)
Format: 9 characters — 6-char issuer + 2-char issue + 1 check digit.
Scope: Securities (equity/debt) of issuers, including public BHCs.
Persistence / reuse rule: Identifies a security, not the legal entity; reassignment is governed by CGS rules.
Datasets that key on it: SEC EDGAR full-text search (searchable field) and securities datasets; for public BHCs it is a join to market data.
Ticker symbol issuer: Listing exchange (NYSE/Nasdaq).
Format: 1–5 alpha characters.
Scope: Exchange-listed securities.
Persistence / reuse rule: Can change or be reused over time across issuers — not a stable entity key.
Datasets that key on it: Market-data joins for public BHCs.

2. Crosswalk — How the Identifiers Map to Each Other¶

2.1 Which identifier is primary in which dataset¶

Dataset / family	Primary key	Also carries
NIC / NPW, FFIEC Call Report, FR Y-9C / FR Y-series	RSSD ID	FDIC Cert, OCC Charter, NCUA id, LEI, ABA RTN, CUSIP, EIN as attribute columns
FDIC datasets (BankFind / SDI / SOD)	FDIC CERT	RSSD (`FED_RSSD`)
SEC EDGAR	CIK	CUSIP, ticker (searchable)
HMDA, 2018-forward	LEI	—
HMDA, 2017 and prior	Agency Code + Respondent ID	Respondent ID = OCC Charter (agency 1), FRS/RSSD (agency 2), FDIC Cert (agency 3), OTS docket (agency 4, legacy), NCUA charter (agency 5), or HUD/CFPB-assigned (non-depository)

NIC carries the FDIC Cert, OCC Charter, NCUA id, LEI, and other identifiers as attribute columns on the RSSD record, which makes NIC the canonical crosswalk hub. The CFPB publishes the ARID2017 → LEI Reference Table (CSV / pipe-delimited) to bridge the pre-2018 and post-2018 HMDA regimes (identifiers FAQ).

2.2 Mapping hazards¶

Sequential-integer collision. RSSD, FDIC Cert, OCC Charter, and NCUA charter are all independent sequential integers starting near 1. The same small integer (e.g. "5") exists in every system as a different institution → an id is not globally unique without its agency/issuer qualifier. HMDA's pre-2018 Agency Code exists precisely to disambiguate. Always carry an agency qualifier when storing or joining these ids.
One BHC → many bank certs. A single top-tier holding company (one RSSD) can own many insured banks, each with its own FDIC Cert and its own RSSD. RSSD↔Cert is therefore many-to-many at the corporate-family level; only at the insured-institution level is RSSD↔Cert roughly 1:1. (See the lead-bank rows in csv/GSIB_ENTITY_IDENTIFIERS.csv — e.g. one JPMorgan BHC RSSD vs. the JPMorgan Chase Bank NA cert.)
Charter conversions. A bank converting between national (OCC) and state-member/non-member status changes the OCC Charter relevance and supervisory agency, but the RSSD ID is designed to persist — making RSSD the most stable join key across charter changes.
Merger / acquisition lineage. When entities merge, the acquired RSSD is closed (moves to NPW "Attributes — Closed") and linked to the survivor via the NIC Transformations table; Certs are retired. A naive id join across vintages that ignores the transformation history will lose merged entities. See docs/NIC_STRUCTURE_GUIDE.md for the Transformations event model (predecessor → successor RSSD, with a transformation type code and date).
LEI coverage gap. LEIs exist only from ~2012 forward and only for entities that obtained one; historical and small entities may lack an LEI, so LEI cannot back-fill pre-2012 panels.
RTN is not an entity key. Routing numbers map many-to-one to institutions, are reassigned on merger, and are reusable across non-concurrent entities; never use an RTN as a persistent entity identifier.
CIK is independent. NIC/NPW carries only an SEC reporting-status flag (SEC_RPTG_STATUS, per the NPW Data Dictionary) — not the CIK; no official CIK↔RSSD crosswalk is published by the SEC, FFIEC, or NIC. Linking SEC public-company data to Fed/FDIC regulatory data therefore requires an external crosswalk, commonly built CIK → FDIC cert → RSSD.

2.3 Real-world example — the difficulty of cross-source linking¶

A concrete illustration of how hard it is to link historical bank panels to the modern RSSD universe: consider a research crosswalk that maps a long-run historical bank-failure panel (covering 1863–1989+) to FFIEC RSSD identifiers via name + state fuzzy matching.

Universe: 14,286 historical banks (panel coverage 1863–1989+).
Matched to RSSD: 943 (6.6%); unmatched (historical): 13,343 (93.4%).
The low overall match rate is by design, not failure: the modern-era (1990+) match rate is 100%, while the pre-FFIEC eras match at 0% — 1934–1959 (5,004 banks), 1914–1933 (5,470), pre-1914 (2,869) are all unmatched because the Fed's RSSD system does not cover banks closed before ~1960. The historical panel's distinctive value is this pre-FFIEC coverage.
Of the matched banks: FDIC cert linked on 495 (52%); BHC linked on 199 (21%).
Match quality: built with a fuzzy-matching threshold of ≥85% similarity (rapidfuzz, grouped by state, +10% city-match bonus); achieved avg confidence 95.4% (min 85.0%, max 100.0%, median 96.7%).

The lesson: even with a robust fuzzy-matching pipeline and a 95%+ average confidence on the matches it does make, an entire era of bank history simply has no RSSD to map to — because the identifier system did not exist yet. Cross-source entity linking is bounded not just by match quality but by the temporal coverage of each identifier system.

3. Sources (official)¶

FFIEC National Information Center (NIC/NPW): https://www.ffiec.gov/NPW
NPW Data Dictionary (authoritative field reference; Doc. Ver. 2.0, Rev. 4/25): https://www.ffiec.gov/npw/StaticData/DataDownload/NPW%20Data%20Dictionary.pdf
NPW Bulk Data download: https://www.ffiec.gov/npw/FinancialReport/DataDownload
CFPB/FFIEC HMDA — Institution Identifiers FAQ (RSSD/Cert/OCC/NCUA/Tax ID/LEI + ARID2017→LEI table): https://ffiec.cfpb.gov/documentation/faq/identifiers-faq
GLEIF — ISO 17442 LEI code structure: https://www.gleif.org/en/about-lei/iso-17442-the-lei-code-structure
GLEIF — LEI data access & use: https://www.gleif.org/en/lei-data/access-and-use-lei-data
FDIC BankFind Suite — API docs: https://api.fdic.gov/banks/docs ; portal: https://banks.data.fdic.gov/bankfind-suite
ABA — Routing Number / registrar: https://www.aba.com/about-us/routing-number
NCUA — Research a Credit Union: https://mapping.ncua.gov/ResearchCreditUnion
SEC EDGAR — Accessing EDGAR Data (REST APIs): https://www.sec.gov/search-filings/edgar-search-assistance/accessing-edgar-data ; Full-text search: https://www.sec.gov/edgar/search/