Deutsche Telekom AG is in early-stage discussions to fully merge with T-Mobile US Inc., a move that would create a telecommunications behemoth valued at nearly $300 billion. The German parent company already controls 53% of T-Mobile's shares. Under the proposed structure, a new holding entity would issue an all-stock bid for both firms and pursue dual listings in the U.S. and Europe.

The potential deal would eclipse the Vodafone-Mannesmann merger of 1999 as the largest public merger in history. Market reaction was immediately negative, with T-Mobile shares falling 3.5% and Deutsche Telekom dropping 5% on Wednesday. Regulatory hurdles loom large, requiring approval from both German and U.S. authorities.

A successful merger would combine Deutsche Telekom's European infrastructure with T-Mobile's 110 million U.S. subscribers, creating the world's most valuable telecom group by market capitalization. The transaction's sheer scale guarantees intense scrutiny from competition watchdogs on both sides of the Atlantic.