Global investors are placing a big bet on Chinese gambling.

Shares of Las Vegas Sands Corp., which operates a lucrative casino in China's Macau territory, have soared 64 percent on the New York Stock Exchange since the company's initial public offering of stock in December. Wynn Resorts Ltd., which is poised to open its own Macau casino in 2006, has jumped 105 percent over the past 52 weeks in Nasdaq Stock Market trading.

But money managers eager to double down their bets are playing two Chinese companies with the most direct exposure to Macau's gambling, hotels, transportation and tourism: Shun Tak Holdings and Melco International Development. Both stocks are listed only in Hong Kong, but U.S. investors can buy them through certain brokers, usually with an additional fee.

Analysts say it is only a matter of time until Macau surpasses Las Vegas as the world's largest and most-profitable gambling and convention center. The former Portuguese colony is just 40 miles from Hong Kong and is the only place on mainland China where casinos are permitted.

"This is a real long-term growth story," says Alexander Muromcew, portfolio manager with TIAA-CREF. The big pension fund -- formally known as Teachers Insurance and Annuity Association-College Retirement Equities Fund _ owns shares of Shun Tak, Melco, and Far East Consortium, a Hong Kong-based property company that is developing Macau casinos.

With Chinese enthusiasm for gambling and the territory's boomtown prospects, there is little doubt these stocks offer a chance to hit the jackpot. But since these stocks already have had a big run and with questions over investor protections _ the odds may be longer than many investors think.

There already are concerns about overdevelopment as new operators rush in hoping to lure the world's high-rollers, many of them Asians, away from Las Vegas. Goldman Sachs warns that the number of Macau gambling tables is poised to rise to 3,700 by 2008 from 845 at the end of last year. That compares with about 2,500 tables currently on the Las Vegas strip. "If demand fails to meet the new supply, this could lead to declining returns in Macau's gaming sector," Goldman says.

Merrill Lynch, meanwhile, forecasts that 2004 gambling revenue was $5.2 billion in Macau, an increase of nearly 50 percent over the previous year. That compares with about $5.3 billion in revenue last year for the casinos along the Las Vegas strip. Macau's gamblers also are skewed decidedly toward high-stakes games like baccarat, while Las Vegas gamblers lean toward slot machines and other mass-market games, such as blackjack and roulette.

Investors also have raised concerns about the treatment of minority shareholder rights and, more seriously, over lingering crime and corruption. Last year, a Macau casino operated by longtime gambling kingpin Stanley Ho faced media allegations of a money-laundering plot that enabled mainland tourists to circumvent currency-exchange limits on people leaving China. Mr. Ho has denied any wrongdoing.

Foreign investors know that many of China's most-promising stocks have faltered on unforeseen difficulties or problems with management. And for all of China's vast potential, few fund managers have been able to translate the country's rapid economic growth into profitable investments. Some already are skeptical about the relative value of the gambling sector.

"In an industry where there is a history of underreported earnings, these stocks are risky plays," says Constance Hunter, managing partner at Coronat Capital Management, a New York-based hedge fund, which doesn't have any holdings in Macau. "There are a lot of other China investments that look less risky."

Still, even skeptics acknowledge that Macau has evolved significantly over the past few years.

The Portuguese legalized gambling there in the 19th century, and the territory was returned to Beijing in 1999. Gambling had long run as a government-sanctioned monopoly until 2002, when the Macau government liberalized the industry by awarding three licenses.

One license went to a group run by the 83-year-old Mr. Ho, who controls Shun Tak and whose son, Lawrence Ho, 28, is chief executive of Melco. Another license went to Galaxy Casino Co., a joint venture between Hong Kong investors and Las Vegas Sands. The third went to Wynn Resorts. Additional licenses may be granted in the future.

"We believe we have the potential to earn more out of Macau than from Las Vegas," says William Weidner, president and chief operating officer for Las Vegas Sands, which plans to open a second beachhead in Macau, a resort on the territory's Cotai strip, by 2007.

In 4 p.m. composite trading on the Big Board, shares of Las Vegas Sands fell $1.43, or 2.9 percent to $47.62, giving the company a market capitalization of $17.2 billion. In Nasdaq Stock Market 4 p.m. composite trading, the stock of Wynn Resorts, which has a market value of $7.13 billion, fell 3.5 percent, or $2.57, to $70.17.

Shun Tak is the center of it all. While it operates multiple businesses, including many in Hong Kong, Goldman Sachs estimates that its property, transportation, gambling and hotel assets in Macau should account for 88 percent of its net profits by the end of 2008, up from only 30 percent in 2004.

Tourism from mainland China to the territory also is soaring, up to 9.5 million visitors last year, more than four times the number in 2000.

Melco is expected to see gross gambling revenue at its high-end Park Hyatt casino jump to $300 billion in 2009 from $140 billion in 2003, according to Smith Barney.

The brokerage firm also expects Melco to make a bid for a gambling license in Singapore and sees another potential investment in Cotai, an area of Macau that is expected to develop into a Las Vegas-style strip.

But before Macau emerges as the world's pre-eminent gambling center, these stocks could face selling pressure. "The proliferation of the Macau concept is reminiscent of the (technology-media-telecom- munications) bubble" of the late 1990s, Smith Barney says in a report. The brokerage firm rates Melco a "hold" but with a price target of 20 Hong Kong dollars ($2.56).

Following huge gains last year, both stocks have been highly volatile and 3 percent to 5 percent daily moves are common. Shun Tak shares surged 195 percent in 2004, while Melco jumped to HK$19.70 from HK$1.97, though both are down slightly this year.

Shun Tak's shares were unchanged Tuesday on the Hong Kong Stock Exchange at HK$8.25, while Melco fell 1.7 percent to HK$17.55.

As with other family-run Asian conglomerates, minority shareholders often come up on the short end of the stick.

In 2002, Shun Tak offered a rights issue that enabled three of Mr. Ho's daughters, who also were Shun Tak directors, to increase their stake in the company to 11.3 percent from 1.6 percent at a significant discount to its net asset value. Other shareholders weren't given the same opportunity.