Argentina has just created another billionaire. And he isn’t sure it’ll last.

Eduardo Costantini, the majority shareholder of Consultatio SA, has a net worth of $1 billion, according to the Bloomberg Billionaires Index, after shares of the nation’s biggest publicly traded real estate company more than doubled in the past year.

“It’s not nice to be named as a billionaire,” Costantini, 70, said over cups of espresso at his office in the Latin American Art Museum of Buenos Aires, or Malba, which he founded in 2001. “What if your stock is down 50 percent and you are no longer a billionaire?”

Like fellow moguls Jorge Horacio Brito and  Marcos Galperin, Costantini has benefited as the Merval index has jumped 59 percent in 12 months with investors embracing the finance-friendly policies of President Mauricio Macri.

At the same time, Costantini said, the gains may be fleeting. Argentina is in a recession. Galperin’s net worth slipped below $1 billion last week after partner EBay Inc. said it is selling part of its stake in his MercadoLibre Inc. Costantini points to neighboring Brazil, where prominent fortunes have declined as Latin America’s largest economy struggles to move past a political crisis that resulted in the impeachment of President Dilma Rousseff.

Early Fortune

Costantini, whose passions include kitesurfing as well as collecting art, scored his first big deal when he used profits from stock market trading in the 1970s to buy a plot of land and quadrupled his money in a few months. He then set up a brokerage firm, Consultatio, in 1980, and scored millions more by cashing out on an investment in publicly traded Banco Frances. After selling out of the lender, he began making real estate investments, building several Buenos Aires towers and Nordelta, a gated community 30 kilometers (20 miles) north of the city that houses 30,000 people.

He also has a 45 percent stake in the holding company for Consultatio’s U.S. projects, including Oceana Bal Harbour, the $1.3 billion luxury mega resort in Miami that’s nearing completion. In Uruguay, he built a controversial circular bridge designed by architect Rafael Vinoly, that guarantees to bring a development boom to his corner of the beach near the chic resort town of Punta del Este.

Art Recovery

It was Costantini’s love for art that helped lift him up when he was struggling to recover from a 2003 kite surfing accident. He fractured a few vertebrae after wind threw him against the rocks of a lake at his Nordelta development. Laid up in the hospital for months, the first place he went after being released was to an exhibit for Argentine artist Jorge de la Vega at the Malba.