NEW YORK, SEPT. 4 -- Troubled loans for real estate and leveraged buyouts are adding to the burdens of the nation's biggest banks and hindering recovery from past mistakes in lending to developing nations, Moody's Investors Service Inc. said today.

In a pessimistic annual review, the credit rating agency said the 1990s may be the decade in which some powerful regional institutions challenge the supremacy of the nationwide "money-center" banks.

While the creditworthiness of most of the nine money-center banks has steadily declined since the 1970s, problems have accelerated in recent years with credit-rating reductions.

Moody's said in a 37-page report that major trouble spots for banks are $55 billion in commercial real estate loans, inadequate reserves to cover nonperforming loans to developing countries and a large exposure to buyouts and other high-risk transactions.

The nine money-center banks are BankAmerica Corp., Bankers Trust New York Corp., Chase Manhattan Corp., Chemical Bank Corp., Citicorp, Continental Bank Corp., First Chicago Corp., Manufacturers Hanover Corp. and J.P. Morgan & Co.

The report said that all the money centers except J.P. Morgan and Bankers Trust are undercapitalized because of "the sharp deterioration in domestic asset quality and low domestic reserves."

Moody's said it was not clear the banks could rebuild capital quickly enough to absorb additional provisions against domestic and developing country loans, which might be required.

The most recent round of credit-rating downgrades affecting Citicorp and other giants were prompted by the real estate slump, and Moody's offered no promises that further downgrades could be avoided.

Moody's said vacancy rates remain high in big cities, which appear to be overbuilt, and that construction loans of all types are "potentially troublesome, particularly for hotels and strip shopping centers."

Market psychology has deteriorated, as the savings and loan scandal has forced many regional and money-center banks to reduce new real estate lending. That has put developers under pressure and made existing properties tough to sell, Moody's said.

The credit agency listed Texas, Arizona, New England, Oklahoma, Tennessee and Colorado as "highly distressed" markets. It said "significant risk elements" exist in New Jersey, Georgia, Maryland, Virginia, Pennsylvania, California, New York and Florida.

Chemical Bank had the largest percentage of nonperforming commercial real estate loans -- those on which no interest is being paid -- at 15.5 percent, followed by Citicorp at 13.9 percent and First Chicago at 12.6 percent. J.P. Morgan had by far the lowest rate, 0.4 percent.

Overall, 11.4 percent of the banks' $54.9 billion in commercial real estate loans outstanding in March were described as nonperforming, the report said.