LEI lookup API

Q: How do I look up a business by LEI?

Call GET /v1/business?lei=.... KnowFirm returns a canonical entity resolved across sources, with crosswalked identifiers (CIK, EIN, FDIC), confidence, and provenance.

An LEI (Legal Entity Identifier) is a 20-character ISO 17442 code that uniquely identifies a legal entity in financial transactions, issued through GLEIF (the Global Legal Entity Identifier Foundation). KnowFirm lets you look up a business by its LEI in one API call and crosswalk it to other identifiers.

One call

curl -H "X-API-Key: $KNOWFIRM_KEY" \
  "https://api.knowfirm.com/v1/business?lei=5493001KJTIIGC8Y1R12"

KnowFirm resolves the LEI to a canonical entity and merges every source that refers to the same business on shared strong identifiers — so a single LEI lookup can also return the company's SEC CIK, IRS EIN, FDIC certificate, address, and a confidence score, each with provenance pointing back to its source.

Why use a resolution API instead of the raw GLEIF record?

The raw GLEIF record gives you the LEI registration. KnowFirm adds cross-source entity resolution: it links the LEI to the same company's records in SEC, IRS, and FDIC data, so you get one merged, deduplicated view instead of querying each registry separately and reconciling them yourself.

Data source

LEI data comes from GLEIF, published under a CC0 (public-domain) license. See Data sources & attribution.

FAQ

What is an LEI? A Legal Entity Identifier is a 20-character ISO 17442 code that uniquely identifies a legal entity in financial transactions, issued via GLEIF.

How do I look up a business by LEI? Call GET /v1/business?lei=.... KnowFirm returns a canonical entity resolved across sources, with crosswalked identifiers (CIK, EIN, FDIC), confidence, and provenance.

Where does KnowFirm's LEI data come from? From GLEIF, the Global Legal Entity Identifier Foundation, which publishes LEI reference data under a CC0 public-domain license.

Can I get the SEC CIK or EIN from an LEI? Often yes — KnowFirm crosswalks the LEI to the same company's SEC and IRS records when they share strong identifiers, and reports each value's source in provenance.