Kabel Deutschland, Germany's largest cable network operator, has pledged to triple its investment in internet service upgrades to secure regulatory approval to get even bigger.

Last week, Bundeskartellamt, the German Federal Cartel Office rejected Kabel's €2.7bn ($3.3bn) bid for regional cable companies, Ish, Iesy and Kabel Baden-Württemberg, which is owned by Blackstone, a private equity firm.