(FORTUNE Magazine) – Cuba's real miracle? The fact that Fidel Castro is still hanging on. The economy is decaying rapidly without the prop of Soviet aid, and rumors persist that the dictator's health isn't much better. The U.S. virtually bans firms from doing business there as long as Castro is in charge. Even so, some corporations are preparing for when he is not. For example, BellSouth, Hyatt, Royal Caribbean Cruises, Lazard Freres, and others are supporting research into how to resurrect Cuba's economy and privatize its businesses. Among the country's attractions: a cheap labor force, fertile land, and a large entrepreneurial class in exile. When U.S.-Cuban barriers do come down, small investors will also have a way to participate. Thomas J. Herzfeld, who runs his own investment firm in Miami, has filed with the Securities and Exchange Commission to register two closed- end mutual funds: First Cuba Fund and Cuba Fund. First Cuba is expected to invest in industries that the country could be strong in, such as tourism, sugar, and rum. The second fund will put money into companies that rebuild the country's highways, telephone system, and other infrastructure. But there's no rush. And that goes for corporations too. Says Jaime Suchlicki, a University of Miami professor who has done studies for several companies on future opportunities in Cuba: ''I tell companies, 'Buy the suitcases, but don't pack them yet.' Fidel could last another three to four years. He could also be followed by a military regime.''