Deutsche Telekom is exploring a full-scale merger with T-Mobile US, according to a report from Bloomberg. The agency suggests that the German group is working on a new holding company structure that would launch an all-stock offer for both Deutsche Telekom and T-Mobile to bring the companies under a single umbrella. T-Mobile shares gained approximately 5% following the news before quickly losing these gains.

The transaction would mark a step-change for Deutsche Telekom, which already holds a 52.8% controlling stake in T-Mobile. It would simplify a group where the US subsidiary drives the bulk of growth and value creation, while the German parent company continues to trade at a conglomerate discount.

However, the plan remains highly preliminary, as such a structure would require significant political backing from both Berlin and Washington. The German state and the public development bank KfW collectively hold around 28% of Deutsche Telekom as of late 2025. If completed, the deal could become the largest M&A transaction ever contemplated between listed companies and would create the world's largest mobile operator by market capitalization, surpassing China Mobile, which is valued at approximately $234.7bn.