Casino stocks have suffered the fate of the broader market over the last several weeks, falling about 5% as investors fretted the bull run was over. But with Wall Street continuing to boost earnings estimates on casino operators, their stocks may be worth a gamble. On Tuesday, a number of Wall Street brokerages raised their earnings estimates on gambling companies, telling investors that fundamentals, especially with regard to room pricing, are stronger than expected. J.P. Morgan upped estimates on Mandalay Resort Group ( MBG) and Ameristar Casinos ( ASCA). Bank of America boosted estimates for Mandalay and MGM Mirage ( MGG), as did Merrill Lynch. In a down market, the rising estimates are the latest in a string of bullish news. Standard & Poor's issued a rosy note on the gaming industry on Monday afternoon, telling bond investors that the industry is maturing and appears healthy. Two weeks ago , Caesars Entertainment ( CZR) started the trend, when it preannounced higher first-quarter results. While many believe that an industry that had massive gains last year -- the Dow Casinos rose 61% in 2003 -- could be overvalued, the underlying trends for the casino industry are extremely strong. The point was hammered home in J.P. Morgan's Gaming & Lodging Conference last week, prompting analyst Harry Curtis to up his estimates on Tuesday. Las Vegas results are impressive, driven in part by easy comparisons. But nickel-and-dime leisure travelers are being replaced by lucrative conventioneers, which has been driving big gains to revenue per available room, a key metric called RevPar. In the second week of April, a survey of room rates on the Las Vegas Strip showed the average room came in at $210, 67% higher than last year. "The greater group demand is displacing our lower-rated tour and travel customers and carries an incremental value per room per night of over $100," said Curtis, noting this trend is what prompted his estimate boost. "For the first time in three years, operators in Las Vegas are showing meaningful expansion in earnings before interest, taxation, depreciation and amortization margins."