The Wertpapierkennnummer, (WKN, WPKN, WPK or simply Wert), is a German securities identification code. Six digits or capital letters (excluding I and O), no check digit. == Changes in format == 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 ma...