The deployment of 1&1's mobile network infrastructure is currently being investigated by Germany's antitrust watchdog, the Bundeskartellamt, to determine whether Vodafone Germany or a subsidiary, Vantage Towers, infringed on the law.

The agency stated in a statement that it began its assessment in response to a complaint made by 1&1.

From the standpoint of competition, Andreas Mundt, head of the Bundeskartellamt, said he welcomed 1&1's proposed market entry as a fourth mobile network operator in Germany. He stated that it is obvious that a company must make significant financial investments and take business risks to build its mobile phone network. Therefore, setting equitable norms of engagement for businesses' commercial practices is a core responsibility of competition law. Companies that are strong and dominating cannot unjustly obstruct other businesses. As a result, he said, 'Bundeskartellamt will carefully consider whether there are good reasons for a delay in deploying antenna positions for 1&1'.

Regardless of the ongoing investigation by the competition regulator, the German government is currently evaluating the possibility of imposing fines on 1&1 for failing to fulfill its obligation related to its acquisition of frequencies in a 2019 auction, to deploy 1,000 5G base stations within a specified timeframe. 1&1 has recently announced its anticipation to introduce 5G services for smartphone users in the third quarter of 2023