German Securities Identifiers: Complete WKN & ISIN Guide

Last updated: February 2026 · 11 min read

Germany's financial market has a unique dual-identifier system: the homegrown WKN (Wertpapierkennnummer) and the internationally standardized ISIN. Understanding both is essential for anyone investing in or working with German securities. This guide covers everything from the historical origins of WKN to practical conversion methods.

The Two Systems at a Glance

History of the WKN

The Wertpapierkennnummer was introduced in 1955 by the German banking industry association (Bundesverband deutscher Banken) to create a standardized way to identify securities across Germany's fragmented banking system. At the time, Germany had multiple regional stock exchanges—Frankfurt, Munich, Stuttgart, Düsseldorf, Hamburg, Hannover, Berlin, and Bremen—each with their own listing conventions.

Originally, WKNs were purely numeric 6-digit codes, allowing for up to 1 million unique identifiers. This seemed ample in the 1950s, when the number of securities traded in Germany numbered in the low thousands.

By the early 2000s, the explosion of derivative products (Zertifikate, Optionsscheine) created a demand for more identifiers. In 2003, the WKN system was expanded to include alphanumeric characters (A-Z), increasing the theoretical capacity to over 2.17 billion unique codes. This is why newer WKNs like BAY001 (Bayer AG) contain letters.

WKN Structure and Format

A WKN is always exactly 6 characters long and can contain:

• Digits: 0-9
• Uppercase letters: A-Z
• No special characters, spaces, or lowercase
• No check digit (unlike ISIN, CUSIP, or SEDOL)

WKNs are assigned sequentially within blocks. Historically, certain ranges were reserved for specific security types:

ISIN Structure for German Securities

German ISINs follow a predictable pattern that directly incorporates the WKN:

German ISIN:  DE  000  766403  9
              ^^  ^^^  ^^^^^^  ^
              |   |    |       |
              |   |    WKN     Luhn check digit
              |   Zero padding
              Country code (Deutschland)

This structure means that for any German ISIN:

• Characters 1-2 are always DE
• Characters 3-5 are always 000
• Characters 6-11 are the WKN
• Character 12 is the Luhn check digit

Major German Securities: WKN and ISIN Reference

Where to Look Up WKN and ISIN

Free German Resources

• boerse-frankfurt.de — Official Börse Frankfurt website. Search by name, WKN, or ISIN. Shows complete Stammdaten (master data) including both identifiers.
• finanzen.net — Germany's most popular financial portal. Every stock page prominently displays WKN and ISIN.
• onvista.de — Comprehensive securities database with WKN/ISIN search.
• ariva.de — Free stock data with WKN/ISIN lookup.
• wallstreet-online.de — Community-driven financial portal with comprehensive identifier data.

German Broker Platforms

All major German brokers display both WKN and ISIN:

• Trade Republic: Tap any security → scroll to "Stammdaten"
• Scalable Capital: Security detail → "Kenndaten"
• comdirect: "Informer" section → search → "Stammdaten" tab
• ING DiBa: Wertpapiersuche → shows WKN and ISIN in results
• Consorsbank: Wertpapierinformation → "Steckbrief" tab

WKN in German Tax Reporting

German tax authorities and the annual Steuerbescheinigung (tax certificate) from your broker use both WKN and ISIN. When filing your Anlage KAP (capital gains tax form), you'll see securities identified by ISIN. However, when contacting your bank or searching for securities in their systems, WKN is often the faster lookup method because it's shorter and more memorable.

For Abgeltungssteuer (flat tax) purposes, the ISIN is the definitive identifier used in tax reporting systems. If you're reconciling dividend income or capital gains across multiple brokers, ISIN is the safest key to use, as WKN assignments can theoretically change (though this is extremely rare).

International Securities with German WKNs

An important distinction: WKNs are not limited to German-issued securities. WM Datenservice assigns WKNs to any security that's traded on a German exchange, including:

For these international securities, the WKN cannot be derived from the ISIN because the ISIN uses the national identifier of the security's home country (CUSIP for US, SEDOL for UK, etc.), not the German WKN. A database lookup is required.

Frequently Asked Questions

Will the WKN ever be fully replaced by ISIN?

Unlikely in the foreseeable future. While ISIN is the official regulatory standard, WKN is deeply embedded in German financial culture. Millions of German investors, financial advisors, and banking professionals use WKNs daily. The system costs nothing to maintain alongside ISIN, so there's no incentive to retire it.

Can two different securities have the same WKN?

No. WKNs are unique identifiers. However, when a company undergoes a corporate action (merger, stock split, rebranding), a new WKN may be assigned. The old WKN is retired but not recycled. Historical WKNs remain associated with the original security.

How do I convert a WKN to ISIN if I don't know the country?

If you have a WKN but don't know whether the security is German or international, the safest approach is to use a lookup service like our converter tool. For German securities, you can construct the ISIN manually (DE000 + WKN + check digit). For international securities, a database lookup is required.

What is WM Datenservice?

WM Datenservice (part of the WM Gruppe) is Germany's National Numbering Agency (NNA), appointed by ANNA (Association of National Numbering Agencies). They are responsible for assigning both WKNs and ISINs for German securities, as well as WKNs for international securities traded in Germany.