Some 340 to 440 banks are expected to fail by the end of next year, while 145 thrifts are at risk of folding, regulators warn, offering new evidence that troubles in the nation's financial sector are far from over.

The grim predictions show that the mass of risky loans, compounded by fallout from the recession, have yet to exact their full toll on the nation's shaky financial institutions.The Federal Deposit Insurance Corp. said it expects hundreds of banks to fail this year and in 1992, holding combined assets of between $95 billion and $160 billion.

John Bovenzi, deputy to the chairman of the federal agency, told a banking conference in Chicago that the failures will probably cost the FDIC's bank deposit insurance fund anywhere from $15.8 billion to $24 billion.

The fund that insures bank deposits is already at a record low compared to the amount of money it covers, and the FDIC has warned that the fund could run out of cash by year's end if the recession persists.

Banks across the nation have been hit by slumping real-estate values and souring loans, forcing regulators to step in, close bank doors and pay off depositors.

But Bovenzi said that at the moment, the situation was better than the grim projections suggested.

During the past four years, 800 banks with about $140 billion in assets have been closed or reserved for closure by the FDIC, costing the fund $23 billion.

Bovenzi told a conference sponsored by the Federal Reserve Bank of Chicago that in 1990, 1,046 commercial and savings banks were on the FDIC's "problem list" with assets of $408.8 billion.

That compares with 1,109 problem banks in 1989, holding combined assets of $235.5 billion.

And weakness in the thrift industry - which has been hit by failure after failure in recent years - also looks set to persist.

In New York, Office of Thrift Supervision director Timothy Ryan said 145 thrifts with assets topping $100 billion are currently at risk of failure.

Ryan, whose agency oversees the battered savings and loan industry, told reporters that he expects these thrifts to be dealt with by year-end.

Fraud, mismanagement and bad loans brought scores of once-healthy thrifts to their knees and bailing out the industry is expected to cost taxpayers $500 billion.

After regulators seize control of a thrift, the cleanup bill lands straight in the taxpayer's lap.

In the past two quarters, 10 to 15 of the thrifts in the likely-to-fail category have returned to health, Ryan said. But in the fourth quarter, 40 to 50 problem institutions were added to the likely-to-fail groups, he added.