Casino stocks have been on a roll, and some investors are betting on continued strong growth in Las Vegas and gains from industry expansion as far afield as China.

But despite the lofty levels, some on Wall Street still think there's room for more gains. Notably, Merrill Lynch's David Anders, who lifted his price targets on shares of Harrah's Entertainment ( HET) to $83 from $72 and MGM Mirage ( MGG) to $80 from $65.

Those price targets would imply enterprise value-to-EBITDA -- or earnings before interest, taxes, amortization and depreciation -- multiples of 8.6 times for Harrah's and 10.6 times for MGM Mirage, at the high end of historic valuation ranges, wrote Anders in a research note.

Nonetheless, the analyst believes such valuations are warranted. In Harrah's case, the company will enjoy synergies and increased cash flow from its pending acquisition of Caesars Entertainment ( CZR), as well as long-term growth opportunities in Pennsylvania, the U.K. and Singapore. MGM Mirage, which is in the process of acquiring Mandalay Resort Group ( MBG), has "meaningful" growth opportunities in Las Vegas and the U.K., among other places.

Shares of both MGM Mirage and Harrah's established new 52-week highs Friday, with MGM Mirage hitting $69.49 and Harrah's rising as high as $64.90, capping off a week of casino stock buying that lifted the Dow Jones U.S. Gambling Index more than 2% last week. Another big casino stock, casino tycoon Steve Wynn's Wynn Resorts ( WYNN), gained about 7% over the week.

A new entrant's dazzling debut helped buoy the sector. Las Vegas Sands Corp. ( LVS) shares soared to almost $50 after the company priced its initial public offering at $29 a share. The IPO price was well above the revised $24-to-$26 target and an earlier range of $20 to $22 a share.

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