The story
Mannesmann Arcor AG & Co. KG was formed in 1996 as a joint venture between Mannesmann, Deutsche Bank and DBKom, a subsidiary of Deutsche Bahn, the national railway operator. After Mannesmann was acquired by Vodafone, the company was renamed Arcor AG & Co. KG.
On 19 May 2008, Vodafone acquired the minority shareholdings of Deutsche Bahn and Deutsche Bank (18.17% and 8.18%, respectively) to gain full control of Arcor.
From Wikipedia’s article on Arcor (telecommunications), shared under CC BY-SA 4.0.4