Spanish telecommunications company Telefonica S.A. (NYSE:TEF) is reportedly poised to announce a $6 billion deal to take over E-Plus Group, a player in the German mobile telecom market, from the Netherlands' Koninklijke KPN N.V. (AMS:KPN), a telecommunications services provider.

The acquisition was expected to be announced Monday, according to an exclusive from the Financial Times, citing two people close to the negotiations. If confirmed, the deal would see KPN acquire a small piece of Telefónica Deutschland, while Telefónica would own a majority stake in the combined entity, valued at 16 billion euros.

If confirmed, the new entity would be fighting for market share in the highly competitive German mobile market, the European Union’s largest with about 114 million subscribers, according to Reuters.

KPN has been pushing to move its market share up from about 15 percent to 20 percent against major competitors Deutsche Telekom AG (FRA:DTE) and Vodafone Group Plc (Nasdaq:VOD) Telefónica and KPN have teased an acquisition deal for years, and in April the two sides reinitiated talks. EU regulators would likely expect concessions to allow this consolidation.

One of the people who spoke to the Financial Times said the acquisition has the backing of Mexican magnate Carlos Slim, KPN’s largest stakeholder.

The news had yet to be publicly announced as of 11:15 a.m. EDT, but KPN’s stock rocketed more than 10 percent to 1.76 euros ($2.32) in afternoon trading in Amsterdam. Telefónica’s ADR stock began climbing around the same time Monday in New York, up 1.54 percent to $13.17.