 In response, American investor Paul Singer’s firm, Elliott Associates, and other hedge funds, which together owned about $700 million of Vitro’s old debt, claimed that Martínez had helped Vitro “muscle investors out of hundreds of millions of dollars through financial sleight of hand,” and accused Vitro of “audacity, brazen manipulation and greed.” Singer and the hedge funds sued Vitro and Fintech in the U.S., where a Dallas court ruled in their favor in summer 2012.An appellate court trial began in October.This legal battle, reported the "Times", was “drawing back a curtain on Mr. Martínez’s secretive world” and “could have implications for other companies in the world’s fastest-growing economies.” Arturo Porzecanski, economist in residence at American University's School of International Service, told the Times that the case “highlighted apparent loopholes in the bankruptcy law of Mexico, through which Vitro ran an 18-wheel truck.”

The "Financial Times" published an article by Martínez on March 7, 2013, in which he argued that Judge Griesa's “interference” might “make future sovereign restructurings impossible, setting a dangerous precedent for the world’s financial system.” Succumbing to “the demands of holdout creditors,” wrote Martínez, Griesa had ordered the Argentinian government to pay them $1.3 billion.