What Is a WKN? Germany's Securities Identification Number Explained

Last updated: July 2026 · 10 min read

A WKN (short for Wertpapierkennnummer, German for "securities identification number") is a 6-character alphanumeric code used to identify financial securities in Germany. If you've ever opened an account with a German broker or looked up a stock on Börse Frankfurt, you've almost certainly seen one sitting right next to the ISIN.

What Does WKN Stand For?

WKN is the abbreviation of Wertpapierkennnummer, which translates literally to "securities identification number." It's a purely German identifier — unlike the ISIN, it has no international standard behind it, and it's only used within Germany and, informally, among traders who deal with German securities elsewhere in German-speaking Europe.

The WKN is issued and maintained by WM Datenservice (Wertpapier-Mitteilungen), a Frankfurt-based data service that has served as Germany's national numbering agency for securities since the identifier's inception. WM Datenservice is also the agency responsible for assigning the German-registered portion of ISINs, which is why the WKN and the German ISIN are so closely linked (more on that below).

A Short History

The WKN system was introduced in 1955, decades before the ISIN existed. At the time it was purely numeric — a 6-digit code assigned sequentially to each new security as it came to market. This numeric-only format stayed in place for decades and is still visible today: most WKNs issued before the early 2000s are all-digit codes, like Siemens' 723610 or SAP's 716460.

As the number of securities requiring identifiers grew — especially with the explosion of funds, certificates, and derivative products in the late 1990s and 2000s — the purely numeric pool of six-digit combinations began running low. To keep up, WM Datenservice made the WKN alphanumeric starting in 2003, allowing letters to be mixed with digits. This is why newer WKNs, particularly for certificates and structured products, often start with a letter (for example, many warrants and certificates use codes beginning with A0, A1, A2, or A3).

WKN Structure

A WKN is always exactly 6 characters long and can contain both letters and digits. There's no fixed internal structure the way an ISIN has (country code + national code + check digit) — a WKN is simply a unique code assigned in sequence by WM Datenservice, with no embedded meaning in its characters, no country code, and no official check digit for validation.

• Length: always 6 characters
• Characters: uppercase letters and digits (alphanumeric since 2003; purely numeric for older listings)
• Issuer: WM Datenservice (Frankfurt)
• Check digit: none — unlike the ISIN, the WKN has no built-in validation mechanism
• Scope: Germany only; not used internationally as a standalone identifier

How the WKN Relates to the German ISIN

Every German ISIN is built directly around its WKN. The structure is straightforward: take the country prefix DE, add three zeros as padding, insert the 6-character WKN, and append a Luhn check digit calculated over the whole string. That gives the standard 12-character ISIN format.

Example: SAP SE

WKN:   716460

ISIN:  D E 0 0 0 7 1 6 4 6 0 0
       ─── ─── ────────── ─
        │    │      │      │
        │    │      │      └─ Check digit (Luhn algorithm)
        │    │      │
        │    │      └─ WKN: 716460
        │    │
        │    └─ Padding: 000
        │
        └─ Country code: DE (Germany)

Result: DE0007164600

Because the WKN is embedded inside the ISIN for every German security, converting between the two is mechanical: strip the DE000 prefix and the trailing check digit from the ISIN, and what remains is the WKN. Going the other direction, pad the WKN into the DE000 + WKN template and calculate the check digit. Our ISIN to WKN Conversion guide walks through this in detail, including edge cases where the relationship isn't quite so clean (for example, some older or reassigned WKNs).

Where Investors See WKNs

If you invest through a German broker, the WKN shows up constantly — often more prominently than the ISIN, especially on older platforms that predate the EU's push toward ISIN-first reporting under MiFID II.

• comdirect — WKN is shown alongside the ISIN on every security's detail page and is searchable directly
• ING (Germany) — order forms and watchlists display the WKN as a primary identifier
• Trade Republic — instrument pages show both WKN and ISIN, with the WKN often used in the search bar
• Börse Frankfurt — every listing page shows WKN and ISIN side by side, plus the ticker symbol
• German fund prospectuses and Wertpapierabrechnungen (trade confirmations) — traditionally reference the WKN, a holdover from before ISIN became mandatory for EU reporting

Outside Germany, the WKN is rarely used — international brokers, data vendors, and regulators default to the ISIN. But for anyone trading German equities, funds, or certificates domestically, the WKN remains the everyday shorthand.

WKN vs ISIN vs Ticker

These three identifiers often appear together on a security's detail page, but they serve different purposes:

In practice: use the ticker for quick verbal or visual reference on a single exchange, the WKN when dealing with a German broker or German-language financial documents, and the ISIN whenever you need an identifier that works unambiguously across borders, brokers, and regulators. For the full picture of how ISIN compares to CUSIP, SEDOL, and other national identifiers, see our What Is an ISIN Number? guide.

Special WKN Ranges

Not every WKN identifies a plain equity. WM Datenservice groups certain product types into recognizable ranges, which experienced German investors learn to recognize at a glance:

• Investment funds — many mutual funds and ETFs domiciled or registered for German distribution carry WKNs that were historically clustered in specific numeric blocks managed by WM Datenservice, separate from the ranges used for operating companies' equities.
• Derivatives and certificates — warrants, certificates, and other structured products issued after the 2003 alphanumeric switch overwhelmingly use WKNs starting with prefixes like A0, A1, A2, and A3. Because these products are issued in huge volumes — sometimes dozens per day from a single bank — the alphanumeric ranges were essential to avoid running out of codes.
• Older equities and bonds — pre-2003 listings mostly retain short, purely numeric WKNs (five or six digits), a legacy of the original 1955 numbering scheme.

For a broader look at how the WKN fits alongside other German market conventions and identifiers, see our German Securities Identifiers guide.

WKN Examples

Notice that BASF's WKN, BASF11, spells out part of the company name — a nod to how alphanumeric WKNs are sometimes assigned to be memorable, unlike the earlier purely numeric scheme used for Siemens and SAP.

How to Convert Between WKN and ISIN

The fastest way to convert in either direction is to use our Financial ID Translator: paste in a WKN and get the matching ISIN (and other identifiers) instantly, or do the reverse with an ISIN. This avoids manually recalculating the Luhn check digit or having to look up padding conventions.

If you want to understand the mechanics — for example if you're building a system that needs to convert identifiers programmatically — our dedicated ISIN to WKN Conversion guide covers the extraction and construction logic step by step, including how the check digit is calculated and validated.

Frequently Asked Questions