Shareholders of Portugal Telecom have agreed to revised lower stake in a merger with Brazilian telecom operator Oi, maintaining an option for a larger stake in the future, the companies said. Under the new terms of the deal, Portugal Telecom shareholders agreed to a 25.6% stake, lower than a 38% stake originally proposed. Portugal Telecom, however, kept an option to buy back more shares over a six-year period pending recovery of debt owed to the company. Company officials said they expect the new merged entity will be listed on exchanges in Brazil, the U.S. and Europe by mid 2015. The approval of the merger comes ahead of local bidding for 4G band concessions on Sept. 30, as well possible future bid by Oi for assets of Telecom Italia’s TIM Brasil. According to media reports, America Movil, controlled by Mexican billionaire Carlos Slim, has expressed interest in making a joint offer with Oi for TIM’s Brazil operations, which have an estimated worth of around $12 billion. British telecom Vodafone is also reported to have shown an interest in acquiring TIM assets.