There are conflicting reports of who owns Niki. Another source suggests the ownership is as follows......Vollständiger Anteilshaber der NIKI Luftfahrt GmbH, welche die Flüge ausführt, ist die NL AB Beteiligungs GmbH. Von dieser wiederum gehören 50,2 % der Niki Privatstifung eV. Die restlichen 49,8 % gehören der Air Berlin PLC & Co, Luftverkehrs KG über die Gehuba Beteiligungsverwaltungs GmbH.
In summary AB it is suggested still owns 49.8% with the rest owned by a trust Niki Privatstiftung. This information may be out of date, but seems plausible. Fact is that various conflicting communications have been made about who owns what. Only insiders at AB really know.
Latest information in the public domain is that LH, Easyjet and Condor are the airlines interested, with some doubts being expressed regarding competition regulations.