WKN, ISIN and ticker

Three identifiers for the same security. Only one of them is unambiguous worldwide — and it is not the one that appears in most news reports.

The ISIN is the reliable one

It is internationally standardised: a two-letter prefix, nine characters of national identifier, and a check digit. The check digit makes it robust against typing errors — a mistyped ISIN is usually invalid rather than wrong. That is the real reason orders should always be placed on the ISIN.

What the prefix actually says

Here sits the most persistent misconception. The two letters denote the national numbering agency that allocated the identifier — that is, the body with which the security was registered for numbering. They do not denote:

• the registered office or country of incorporation of the company,
• where it does business,
• the exchange on which it trades,
• or its tax treatment.

For the securities we cover, the typical prefixes are:

• CA — allocated in Canada (TSX, TSX Venture, CSE)
• AU — Australia (ASX)
• GB — United Kingdom (AIM)
• US — United States

No substitute for checking. A leading CA does not establish that the issuer is a Canadian company, and a different prefix does not rule out a Canadian listing. Companies listed in Toronto but incorporated in another jurisdiction are nothing unusual in the resources sector. Where a company is established and which law governs it is set out in its own filings — not in two letters.

The WKN is convenient, and local

Six characters, allocated by WM Datenservice in Frankfurt, in use since 1956 and admitting letters since 2003. It is shorter than the ISIN and it is what German brokerage accounts and German price lists display, which is why a security's German page will carry it. Outside the German-speaking market nobody uses it, and a search of a Canadian source with it will return nothing.

For a foreign issuer, this is the identifier under which its own shares exist in the German market. It is not a separate instrument, and it does not travel.

The ticker is the dangerous one

A ticker is valid only on one exchange. The same short code can denote a mining company on the TSX and something else entirely on a US exchange. It is also recycled: when a company disappears, its code can pass to another one years later.

Data services therefore append an exchange suffix to it. Those suffixes are the convention of the individual provider and are not standardised. Something else is standardised: the market identifier code (MIC) under ISO 10383. That is the value to use when an entry has to be unambiguous.

In practice: a suffix is good enough for searching a price portal. As soon as an entry is processed by machine or handed to another party, the MIC belongs there instead.

And one more thing. A company often carries several tickers at once — one at home, one for the US over-the-counter market, one in Germany. It remains the same ISIN throughout.

When identifiers change

The point that really matters in small caps. It is also less clear-cut than it is usually made out to be.

Share consolidation (reverse split). Common at explorers after several equity raises. Whether the identifier changes depends on how the operation is executed; there is no rule that requires the change automatically:

• Where new shares are issued that replace the old ones, the security receives a new ISIN and a new WKN. The old position is booked out of the account and a new one booked in. This is the more frequent case, and the one to plan for.
• Where par-value shares are merely replaced by shares of a higher par value, the identification can stay unchanged.

Neither variant should be relied on. What governs is the company's own announcement and the entry in the account.

Change of domicile or of name. Frequently changes the name and the ticker. The ISIN can change with it, where a different numbering agency becomes responsible.

Merger or takeover. The old identifier lapses.

Why this matters in practice. After any such change, the price history under the old identifier stops. A chart showing "down 90% since 2021" may be concealing a consolidation — or counting it twice. With a striking junior chart, the history of corporate actions is therefore the first thing to check, not the last. See Dilution.

The working rules

1. Search and deal on the ISIN. Always.
2. Use a ticker only with the exchange attached. "ABC" on its own is not an identification.
3. On Canadian sources — SEDAR+, the home exchange — search by name and ticker. The WKN does not exist there.
4. Where a broker cannot find an ISIN, the security is usually simply not tradable there. Spelling is rarely the cause.
5. After a corporate action, check the identifier again before adding to a position.
6. Do not read the country prefix as proof of origin. It is an administrative feature.

Why this page exists

Every piece of analysis on this site opens with the WKN, the ISIN, the home exchange and the German venues. This page explains why those four fields sit at the top rather than in the small print: without them it is not unambiguous which company is being discussed.

Further: How Canadian small caps are traded in Germany · The German venues compared

Sources

Retrieved on 11 August 2026:

• Market identifier codes under ISO 10383 — the registration authority and the continuously maintained list
• Association of National Numbering Agencies — the bodies that allocate ISINs under ISO 6166
• WM Datenservice — allocation of the WKN in Germany
• Toronto Stock Exchange and TSX Venture Exchange · Canadian Securities Exchange — tickers and listings
• SEDAR+ — mandatory filings of Canadian issuers, including announcements of corporate actions

On the shelf life of this page. The standards underneath — ISO 6166 and ISO 10383 — are stable. The practice on top of them is not: provider suffixes, the responsibilities of numbering agencies and the handling of corporate actions all change without announcement. "As of" denotes the date this was last checked. In case of doubt, what governs is what the company announced and what the account records.

As of 11 August 2026 · Version 1 · Not investment advice. Not tax advice.