By Dena Aubin

NEW YORK, Aug 18 (Reuters) - Prices of U.S. casino companies' bonds are collapsing, a sign more bankruptcies may be on the way as lenders take flight and high fuel prices curb travel to gambling resorts.

Investors have lost an estimated 14.2 percent on casino bonds year to date, the second-worst performance of any junk-rated sector after diversified media companies, which are down about 15.9 percent, according to a new report by JPMorgan.

"The expectation was that in a down economic cycle that gaming would still do well, but gaming is showing that it's vulnerable," said Keith Foley, analyst for Moody's Investors Service. "We believe it probably hasn't hit its bottom."

With credit drying up, at least three casino operators -- Greektown Casino in Michigan, Kentucky's Tropicana Entertainment LLC and Illinois-based Legends Gaming -- already have filed for bankruptcy protection this year, and bonds of other major gaming companies are trading in "distressed" territory, a red-alert level that suggests serious default risk.

Foley said smaller, single-property companies with big debt loads are most at risk.

Believing casinos were recession-resistant, bondholders and bankers poured money into the sector during a recent credit boom. Now, with the economy sputtering and gambling receipts down, casinos find themselves with dwindling revenue to support debt, and nervous lenders are backing away.

FINANCING IN DIRE STRAIGHTS

Cash-strapped consumers are still gambling, but they are spending less at card tables or shifting to cheaper slot machines, according to Christopher Snow, analyst at independent research service CreditSights. Financing for casinos is also in dire straights, a concern for companies that depend on expansion to drive growth, he said.