---
title: "ISIN vs ticker vs SEDOL vs WKN vs CUSIP: fund identifiers explained"
description: "What each fund identifier is for, which ones are unique per share class, how they nest inside an ISIN, and which one to use as the key in a database or API."
canonical: https://fundfactsapi.com/blog/isin-vs-ticker-vs-sedol-vs-wkn-vs-cusip
published: 2026-09-13
updated: 2026-09-13
publisher: FundFacts API
---

# ISIN vs ticker vs SEDOL vs WKN vs CUSIP: fund identifiers explained

> What each fund identifier is for, which ones are unique per share class, how they nest inside an ISIN, and which one to use as the key in a database or API.

An ISIN identifies one security worldwide; a ticker identifies a listing on one exchange; SEDOL, CUSIP and WKN are national numbering schemes for the UK and Ireland, North America and Germany respectively. For funds and ETFs the ISIN is the only identifier that is both global and unique per share class, which is why it is the key that databases, custodians and fund data APIs use. Everything else is either local, non-unique or embedded inside the ISIN anyway.

> **In short** An ISIN is 12 characters, global, and unique per share class. A ticker is per exchange: the same ETF has different tickers in London, Frankfurt and Milan. A SEDOL (7 characters) and a CUSIP (9 characters) are the national numbers that sit inside UK/Irish and US ISINs. A WKN (6 characters) is the German national number and is not embedded in the ISIN. Use the ISIN as your primary key and treat the others as aliases.

## Why funds need more than one identifier

A single ETF share class can be listed on five exchanges, held through custodians in a dozen countries, and reported to regulators under several regimes. Each of those systems grew its own naming convention before a global one existed. The ISIN, defined by ISO 6166 and issued by each country's National Numbering Agency, was the attempt to unify them; the older codes did not disappear, they became inputs to it.

The practical problem for developers is that users arrive with whichever code their broker shows them. A German retail investor knows the WKN, a UK adviser quotes the SEDOL, a trader types a ticker, and the fund's own factsheet prints the ISIN. Your product has to accept all of them and resolve to one key. That key should be the ISIN, for reasons the rest of this post makes concrete.

## The five identifiers side by side

| Identifier | Length and format | Scope | Unique per share class? | Who issues it |
| --- | --- | --- | --- | --- |
| ISIN | 12 chars: 2-letter country, 9-char NSIN, 1 check digit | Global | Yes | National Numbering Agencies under ISO 6166 |
| Ticker | 1–6 letters, exchange-specific | One exchange | No: one share class has one ticker per listing | Each exchange |
| SEDOL | 7 chars, last is a check digit | UK, Ireland and some other markets | Yes | London Stock Exchange |
| CUSIP | 9 chars, last is a check digit | US and Canada | Yes | CUSIP Global Services |
| WKN | 6 alphanumeric chars, no check digit | Germany | Yes | WM Datenservice |

Two rows deserve a closer look.

**Tickers are not unique.** The iShares Core MSCI World UCITS ETF (accumulating share class, ISIN `IE00B4L5Y983`) trades as one ticker on the London Stock Exchange, a different one on Xetra and another on Borsa Italiana. Worse, tickers are reused across exchanges for unrelated securities. A ticker only means something together with an exchange code, and even then it identifies a listing, not the underlying share class. The [ticker glossary entry](https://fundfactsapi.com/glossary/ticker) has more on the reuse problem.

**WKN is not embedded in the ISIN.** German ISINs are `DE` + `000` + WKN + check digit, so for a German security you can derive one from the other. But an Irish ETF sold in Germany has an Irish ISIN and a separately assigned WKN that has nothing to do with the ISIN's middle characters. Mapping WKN to ISIN for non-German funds needs a lookup table.

## How SEDOL and CUSIP nest inside the ISIN

The middle nine characters of an ISIN are the National Securities Identifying Number, padded with leading zeros. For the two most common national schemes the nesting is exact:

- **UK and Irish ISINs:** `GB` or `IE` + `00` + 7-character SEDOL + check digit. Take `IE00B4L5Y983`: the SEDOL is `B4L5Y98`.
- **US ISINs:** `US` + 9-character CUSIP + check digit. The CUSIP is positions 3–11 with no padding, because a CUSIP is already nine characters.

This means you can extract the SEDOL from any `GB` or `IE` ISIN with a slice, and the CUSIP from any `US` ISIN. The reverse works too: given a SEDOL and the knowledge that the security is Irish, you can reconstruct the ISIN by prepending `IE00` and computing the Luhn check digit (the [ISIN guide](https://fundfactsapi.com/blog/what-is-an-isin) has the algorithm, and the free [ISIN validator](https://fundfactsapi.com/tools/isin-validator) does it in the browser).

Luxembourg ISINs (`LU`) and French ISINs (`FR`) do not embed a SEDOL or CUSIP. Their NSIN is a national number that has no life outside the ISIN, so for the bulk of UCITS funds domiciled in Luxembourg there is nothing to extract.

```typescript
export function nationalCode(isin: string): { scheme: "SEDOL" | "CUSIP" | "WKN" | "NSIN"; code: string } {
  const cc = isin.slice(0, 2);
  const nsin = isin.slice(2, 11);
  if (cc === "GB" || cc === "IE") return { scheme: "SEDOL", code: nsin.slice(2) };
  if (cc === "US" || cc === "CA") return { scheme: "CUSIP", code: nsin };
  if (cc === "DE") return { scheme: "WKN", code: nsin.slice(3) };
  return { scheme: "NSIN", code: nsin.replace(/^0+/, "") };
}

nationalCode("IE00B4L5Y983"); // { scheme: "SEDOL", code: "B4L5Y98" }
nationalCode("LU1681043599"); // { scheme: "NSIN", code: "1681043599" } — no separate national scheme
```

## Which identifier should be your primary key?

The ISIN, every time. The reasoning:

1. **It is unique per share class.** Accumulating and distributing classes, hedged and unhedged, retail and institutional each have their own ISIN. That is exactly the granularity fees, NAVs and performance are reported at. See [share classes explained](https://fundfactsapi.com/blog/fund-share-classes-acc-dist-hedged-explained) for why this matters.
2. **It is global.** One key works for an Irish ETF, a Luxembourg SICAV, a French FCP and a US mutual fund.
3. **It has a check digit.** You can reject typos before they cost a lookup. The [ISIN glossary entry](https://fundfactsapi.com/glossary/isin) covers the format.
4. **It is what the documents print.** Factsheets, KIDs and prospectuses carry the ISIN; many carry no ticker at all.
5. **It is what data APIs accept.** [FundFacts API](https://fundfactsapi.com/) resolves a fund from its ISIN alone: `GET /api/v1/funds/{isin}` returns the structured factsheet, and the batch, portfolio and overlap endpoints take lists of ISINs.

The other codes become alias columns. A pragmatic schema is a `securities` table keyed by ISIN with nullable `sedol`, `cusip` and `wkn` columns, and a separate `listings` table with `(isin, exchange, ticker, currency)` rows, because one ISIN has many listings.

## Resolving what users type

The input box on a fund search should accept anything and normalise it. A reasonable order of attempts:

1. Strip whitespace, upper-case. If it matches `^[A-Z]{2}[A-Z0-9]{9}\d$` and passes the check digit, it is an ISIN. Done.
2. If it is 7 characters ending in a digit, treat it as a SEDOL candidate; if 9 characters, a CUSIP; if 6, possibly a WKN. Look it up in your alias table.
3. Otherwise treat it as a name or ticker and run a text search. FundFacts exposes `GET /api/v1/search?q=` for this, which matches the exchange tickers of listed ETFs (`VWCE`, `EUNL`, `CSPX`) and ISIN prefixes first, then fund name and issuer, and returns the ISIN for each hit. Search is free on every plan.

```bash
curl "https://fundfactsapi.com/api/v1/search?q=core%20msci%20world&limit=5" \
  -H "Authorization: Bearer ffk_live_..."
```

```json
{
  "query": "core msci world",
  "count": 5,
  "results": [
    { "isin": "IE00B4L5Y983", "name": "iShares Core MSCI World UCITS ETF USD (Acc)", "issuer": "iShares", "currency": "USD", "assetClass": "Equity", "shareClass": "USD Acc", "url": null }
  ]
}
```

Once you have the ISIN, the [factsheet lookup](https://fundfactsapi.com/blog/fund-data-api-from-isin) is one call, and the response's `isin` envelope field echoes the canonical upper-case code so you can store it.

## Edge cases worth handling

- **One ISIN, several currencies.** An ETF share class can be listed in USD in London and in EUR in Frankfurt under the same ISIN. The listing currency is a property of the listing, not the security. `keyFacts.currency` in a fund payload is the share-class base currency, which is fixed.
- **Ticker collisions across asset classes.** A three-letter ticker on one exchange can be a bank on another. Never key anything on a bare ticker.
- **Reissued national codes.** SEDOLs and CUSIPs can be reassigned after corporate events; ISINs are not recycled. Another reason to key on ISIN.
- **Funds without any listing.** Most non-ETF UCITS funds are not exchange traded, so they have an ISIN and possibly a SEDOL or WKN, but no ticker at all. A ticker-first design cannot represent them.
- **Fund of funds.** A fund's [top holdings](https://fundfactsapi.com/glossary/top-holdings) are reported by name, not by identifier, in most factsheets. If you need identifiers for holdings, you will be doing name matching, which is how the [overlap endpoint](https://fundfactsapi.com/blog/how-to-calculate-etf-holdings-overlap) works.

## Where each identifier shows up in FundFacts data

The API is ISIN-native. The envelope of every fund response has `isin` (canonical) and `name`; the `data` object has `shareClass` when it can be inferred, `keyFacts.currency` and `keyFacts.inception`. There is no ticker field, because a ticker without an exchange is ambiguous and the fund's own documents rarely commit to one. If you need tickers for a trading screen, keep them in your listings table alongside the ISIN and join at display time.

For the rest of the identifiers, the [glossary](https://fundfactsapi.com/glossary) has short entries on [SEDOL](https://fundfactsapi.com/glossary/sedol), [CUSIP](https://fundfactsapi.com/glossary/cusip) and [WKN](https://fundfactsapi.com/glossary/wkn). If you are designing a fund database from scratch, the [fund screener tutorial](https://fundfactsapi.com/blog/build-a-fund-screener-with-nextjs) shows a schema keyed on ISIN in practice.

## FAQ

### Can I convert a ticker to an ISIN?

Not by computation. A ticker is assigned by an exchange and carries no information about the security's national number, so ticker-to-ISIN is a lookup, never a formula. Use a search endpoint such as `GET /api/v1/search?q=` or your own alias table, and always combine the ticker with its exchange, because tickers are reused across venues.

### Is the SEDOL inside the ISIN?

For UK and Irish ISINs, yes: the ISIN is the country code, two zeros, the 7-character SEDOL and a check digit. `IE00B4L5Y983` contains the SEDOL `B4L5Y98`. Luxembourg, French and most other ISINs do not embed a SEDOL.

### Do all funds have a ticker?

No. Exchange-traded funds have one ticker per listing, but most traditional UCITS funds are not listed and have no ticker. Every fund share class has an ISIN, which is why an ISIN-keyed data model covers both.

### Is a WKN the same as an ISIN?

No. A WKN is a 6-character German national code without a check digit. For German securities the ISIN is `DE000` followed by the WKN and a check digit, but for foreign funds sold in Germany the WKN is assigned separately and must be looked up.

## About FundFacts API

FundFacts turns any fund or ETF ISIN into one dated factsheet (fees and KID costs, the 1–7 risk indicator, holdings, sector and country exposure, returns) read from the fund house's own documents: as a client-ready PDF under your firm's name for advisers and wealth managers, as JSON through its API for developers, or inside ChatGPT and Claude through its MCP server.

FundFacts works inside ChatGPT and Claude as a connector (a remote MCP server): ask about any fund or ETF by ISIN, ticker or name and the assistant answers from FundFacts' dated figures, fees, risk, holdings, exposure and returns, with fund cards, side-by-side comparisons, holdings overlap and portfolio look-through.

- Free API key, no card: https://fundfactsapi.com/signup
- Documentation: https://fundfactsapi.com/docs (OpenAPI: https://fundfactsapi.com/openapi.json)
- MCP server: https://fundfactsapi.com/api/mcp (set-up for every client: https://fundfactsapi.com/mcp-server)
- Pricing: https://fundfactsapi.com/pricing
- Site index for AI assistants: https://fundfactsapi.com/llms.txt
- Informational data, not investment advice.