 Bloomberg News reported on November 14, 2013, that Fintech Group had agreed to pay $860 million for Telecom Italia SpA's 68 percent holding in Sofora Telecomunicaciones, the controlling holding company of Telecom Argentina through Nortel Inversora, plus a direct minority stake, plus $100 million for related assets, for a total of $960 million.This deal pitted him “against the mobile-phone business of Carlos Slim in South America’s second-biggest economy” and “expand[ed] Martínez’s bets beyond holdings such as cable assets and Argentina’s sovereign debt as he seeks to benefit from increasing Web and video use on mobile devices.”

Bloomberg reported that “Telecom Argentina and the local unit of fellow Mexican billionaire Slim’s America Movil SAB (AMXL) each have about a third of the nation’s wireless market.” Noting that “Fintech has investments in Argentina’s sovereign debt as well as in many restructured companies including a stake in the country’s largest cable company, Cablevisión SA,” Bloomberg quoted Martínez as saying, “We see tremendous opportunities for growth in the Argentine market and are committed to an important investment program to take advantage of those opportunities.”

A "Wall Street Journal" article, published on November 10, 2013, described Martínez's decision to invest in Argentina “an unusual call,” given that “Argentina has been a cautionary tale for many investors since its 2001 default on $100 billion in sovereign debt” and that its last two presidents, Néstor Kirchner and Cristina Kirchner, had “repeatedly gone mano a mano with big business,” nationalizing an oil company and seeking to force the Clarin media group to break up its business.The Journal described Martínez as “part of a small group of investors who are willing to overlook Argentina's status as a financial pariah and bet long term,” in the expectation that “the next government to be more pragmatic and less hostile to business.”

In March 2014 Martínez called together several representatives of funds with holdings in Argentine bonds, with the intention of beginning to negotiate a joint exit for the bondholders.