David Martínez Guzmán may not be a household name. But he's a very, very rich Mexican tycoon who's making inroads among the world's financial elite, and he just bought a sizeable chunk of one of the largest banks in Spain. The “ghost investor,” as several Mexican media outlets have dubbed him, keeps a very low-key public profile: There is barely any news about his moves, or pictures of him on the Internet. There is no estimate of his wealth, although many have said that he is following in the footsteps of fellow Mexican tycoon Carlos Slim to become the richest man in the world.

Martínez Guzmán’s name does not make headlines, but the few there are show that he has a weakness for trying to salvage ruined economies -- or an ability to spot a very good deal. In 1994, he invested in the wrecked Argentinean economy by buying government bonds with a maturity of 37 years for $834 million. He has maintained a close relationship with the Latin American country, where he currently holds 40 percent of Argentinean media group Cablevisión, owner of Clarín, one of the country's biggest news outlets. Martínez Guzmán has even managed to maintain a good relationship with left-leaning Clarín’s biggest opponents, President's Cristina Fernandez de Kirchner's family.

The tycoon has now set his sights on the other side of the Atlantic, to the damaged Spanish economy, where he has bought 5 percent of Banco Sabadell, it was widely reported on Monday. Martínez Guzmán is part of a capital-expansion strategy by the bank, and he is joined by Colombian banker Jaime Gilinski in a 350 million euro ($465 million) investment. Each of them will own 5 percent of the shares and will join the board of directors.

Martínez Guzmán, born in Monterrey in 1957, graduated from the Instituto Tecnológico de Monterrey with a degree in electrical engineering. He switched gears and moved to the financial world with an MBA from Harvard and a post-grad school internship at Citigroup in New York. He returned to Mexico in 1987 and invested $300,000 his grandmother left him to fund Fintech Advisory, a company dedicated to buying debt from economies at risk and bailing out businesses in trouble.

Going after cheap assets from countries in trouble in the hopes they will recover isn't a new strategy, but Guzman does it with serious intellectual firepower behind him. His analysts are the “best of the best,” journalist Bernardo Marín García wrote in Spanish newspaper El País. “They analyze everything to the smallest detail. If they have gone to Sabadell, it is because they are expecting it to go up soon.”

Martínez Guzmán runs his business from New York and London, and in 2003 he bought a two-floor apartment in the Time Warner Towers in Manhattan for $42 million. That was the first time his name made headlines, although he proceeded with the utmost discretion. Both the New York Times and Bloomberg tried to write profiles of him, but he did not give them interviews.

He didn't speak out in 2006, either, when a rumor began that claimed he had spent $140 million on a Jackson Pollock painting for his Manhattan pad. “He was not pleased,” wrote Mexican journalist Wilbert Torre in El Universal. “As he was not pleased when his family became famous in Monterrey,” the Mexican city of their origin.

Torre noted that, besides Martínez Guzmán’s secrecy in all of his affairs, one thing is certain: He will make an appearance in his hometown on Dec. 24 for Christmas Eve dinner, as he has done every year since he left his native Mexico.