Slim controls 32.9 million of YPF’s Class D shares, according to a regulatory filing today from the Buenos Aires-based company. Arturo Elias, a spokesman for Slim, didn’t immediately return a telephone call seeking comment.

Argentina seized 51 percent of YPF from Madrid-based Repsol SA as President Cristina Fernandez de Kirchner’s government seeks to halt declining oil and gas output and stem fuel imports that doubled to $9.4 billion last year. The government wants to tap shale reserves that may hold at least 23 billion barrels of oil equivalent in the country’s south.

YPF’s American depositary receipts surged 14 percent to $11.90 at 4:25 p.m. in New York after the announcement.