# Ticker, ISIN or LEI: find the right European company

> Avoid mixing an issuer with a listing, security or subsidiary. A practical identity checklist for European financial research with AI agents.

By European Financial Data. Reviewed 17 October 2026.

Canonical article: https://eurofindata.com/research/company-identifiers-ticker-isin-lei

## The short answer

A ticker identifies a symbol in a market context, an ISIN identifies a security, and an LEI identifies a legal entity. Resolve the reporting company first and retain its identifiers when joining financial statements and disclosures.

## A company name is a search term, not a join key

A familiar brand can correspond to a parent company, operating subsidiary and several listed securities. A ticker is meaningful in its market context. If an agent joins data using a name or symbol alone, it can silently mix different entities or instruments.

Resolve the reporting company before requesting statements or joining disclosures. Record the returned name, country, exchange context and available identifiers, then compare them with the source you intend to use.

Identifiers have different scopes

| Identifier | What you are identifying | Check before joining |
| --- | --- | --- |
| Ticker and market context | A trading symbol in a particular listing context | Exchange or MIC, share class, and any cross-listing |
| ISIN | A security | Whether two records refer to the same instrument rather than merely the same issuer |
| LEI | A legal entity | The entity that issued the filing and the consolidation scope of the statements |

## Follow a concrete issuer through a filing

The ASML ESEF sources used in our [margin example](https://eurofindata.com/research/asml-operating-margin) identify the entity with LEI `724500Y6DUVHQD6OXN27`. That lets the researcher check that the linked source belongs to the intended legal entity rather than relying only on the word “ASML”.

An LEI is not an accounting-scope guarantee. You still need to check whether the figures are consolidated, their reporting period and the accounting basis. Likewise, different securities issued by the same company can share an issuer relationship while retaining different security identifiers.

## Ask the agent to show its identity checks

### Research prompt

```text
Before analyzing the company I name, search for matching entities in European Financial Data. Show the returned company name, country, ticker and market context, ISIN and LEI where available. If several entities or listings could match, ask me to choose. Check that the statement filing belongs to the intended reporting entity. Retain these identifiers when joining regulatory disclosures; flag an ambiguous or missing match instead of guessing.
```

Connect MCP first; check whether the required data exists.

Use `search_companies` to find candidates, then inspect `get_company_coverage` for the selected company. These tools accept several forms of identifier, but that convenience does not eliminate the need to inspect the resolved entity.

## Keep a record of the join

1. Save the original search term and the resolved identifiers.
2. Identify whether the next dataset is keyed by issuer, security, listing or another entity.
3. Use an explicit mapping and record its source when identifiers differ.
4. Leave an unmatched record unresolved; do not silently use the nearest name.

This matters for short positions, ownership and debt instruments as well as statements. A subsidiary’s legal-entity relationship does not automatically make its figures interchangeable with consolidated parent-company accounts.

## Do not infer an exchange from an ISIN

[ANNA’s identifier guidance](https://anna-web.org/identifiers/) describes ISINs as identifiers for financial instruments. An ISIN is not itself an exchange identifier. Retain market context, such as a MIC, when the question concerns a particular listing or price.

[GLEIF describes the LEI](https://www.gleif.org/en/organizational-identity/lei-vlei/the-legal-entity-identifier-lei) as a legal-entity identifier. A matched LEI helps link a company to its filing, but it does not state that every security or subsidiary has identical accounting scope. If the task concerns an ADR or multiple share classes, resolve that security relationship explicitly.

When there is no unambiguous match, return the candidates and the unresolved identifier instead of selecting the closest name.

## Sources and further reading

- [ANNA: ISIN and other financial identifiers](https://anna-web.org/identifiers/)
- [GLEIF: the Legal Entity Identifier](https://www.gleif.org/en/organizational-identity/lei-vlei/the-legal-entity-identifier-lei)
- [GLEIF: ISIN-to-LEI relationship files](https://www.gleif.org/en/lei-data/lei-mapping/download-isin-to-lei-relationship-files)
- [ASML ESEF source with entity context](https://filings.xbrl.org/724500Y6DUVHQD6OXN27/2025-12-31/ESEF/NL/0/asml-2025-12-31-1-en.json)
- [Our source and freshness documentation](https://eurofindata.com/docs/provenance)

## Put your next company question to work.

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- [Create a free account](https://eurofindata.com/sign-up)
- [Connect your agent](https://eurofindata.com/agents.md)

## Keep exploring

- [Research European short-position disclosures with an agent](https://eurofindata.com/research/european-short-position-disclosures)
- [Build a SAP margin history without filling the gaps](https://eurofindata.com/research/sap-financial-history-missing-data)
- [Where to get European financial data for AI agents](https://eurofindata.com/research/european-financial-data-for-ai-agents)