The Wertpapierkennnummer (WKN, WPKN, WPK or Wert) is a German securities identification code. It is composed of six digits or capital letters (excluding I and O), and no check digit.
There have been several changes in the WKN definition:
The WKNs and DE-ISINs are provided by WM-Datenservice.
WKNs may be obsolete in future, since they may be replaced by International Securities Identification Numbers (ISINs).
Like most very long German words, Wertpapierkennnummer is a compound word: Wert-Papier-Kenn-Nummer, if translated literally, means value–paper–identification–number (Wertpapier = financial security; Kennnummer = identification number).
Before the German spelling reform of 1996 the correct spelling was Wertpapierkennummer with only two consecutive n's, since the orthography rules allowed the same consonant three times in a row only under special circumstances. Since the reform, the spelling has been Wertpapierkennnummer with three consecutive n’s.