But time may be running out for some small and midsize lenders. They vary in size and location, but their common woe is the collapsed real estate market and souring mortgage loans. Most of these banks are far smaller than the industry giants that have drawn so much scrutiny from regulators and investors.

Still, only five lenders have failed so far this year, including IndyMac. In 1994, the Federal Deposit Insurance Corporation listed 575 banks that it considered to be troubled. As of this spring, the agency was worried about just 90 banks. That number may go up in August, when the government releases an updated list.

“Failed banks are a lagging indicator, not a leading indicator,” said William Isaac, who was chairman of the F.D.I.C. in the early 1980s and is now the chairman of the Secura Group, a finance consulting firm in Virginia. “So you will see more troubled, more failed banks this year.”

And yet IndyMac, one of the nation’s largest mortgage lenders, was not on the government’s troubled bank list this spring  an indication that other troubled banks may be below the radar.

The F.D.I.C. has $53 billion set aside to reimburse consumers for deposits lost at failed banks. IndyMac will eat up $4 billion to $8 billion of that fund, the agency estimates, and that could force it to raise more money from the banks that it insures.

The agency does not disclose which banks it thinks are troubled. But analysts are circulating their own lists, and short sellers  investors who bet against stocks  are piling on. In recent weeks, the share prices of some regional banks, like the BankUnited Financial Corporation, in Florida, and the Downey Financial Corporation, in California, have stumbled hard amid concern about their financial health. A BankUnited spokeswoman said the lender had largely avoided risky subprime loans.

In his “Who Is Next?” report over the weekend, Mr. Bove listed the fraction of loans at banks that are nonperforming, meaning, for example, that the assets have been foreclosed on or that payments are 90 days past due. He came up with what he called a danger zone, which was a percentage above 5 percent. Seven banks fell in this category.