More banks may fail after IndyMac: analysts

Cassidy called the probability of failure "very high" if a bank's nonperforming assets exceed the sum of tangible equity plus reserves for loan losses.

In a report on July 13, Richard Bove, a bank analyst at Ladenburg Thalmann & Co, said a "danger zone" is where nonperforming assets, including loans at least 90 days past due, exceeded 40 percent of common equity plus reserves.

"The system is not anywhere near the danger that existed in the late 1980s and early 1990s despite all of the whining by public officials," Bove wrote. "Perhaps, the second quarter numbers will prove them right."

Citing FDIC data as of March 31, Bove said that IndyMac had been at the greatest risk among more than 100 of the largest U.S. lenders, with a 146.2 percent ratio.

BankUnited Financial Corp of Coral Gables, Florida, was among lenders high on Bove's list.

"We're surprised to be near the top of that list," Bert Lopez, BankUnited's chief financial officer, said in an interview. "Our underwriting standards have been very conservative, we have insured a substantial portion of our loan portfolio, and our losses remain low on an overall basis."

He declined further comment, citing a pending $400 million stock offering. BankUnited shares closed Friday at 77 cents. Other banks high on the list did not immediately return requests for comment.

The FDIC has said it will reopen IndyMac on Monday as IndyMac Federal Bank, and then try to sell the company as a whole or in pieces. Regulators expect the takeover to cost the FDIC $4 billion to $8 billion. The agency insurance fund has about $52.8 billion.

Among IndyMac's assets are its deposits, 33 southern California branches, its Financial Freedom reverse mortgage unit, and a fast-deteriorating loan book.

Cassidy said thrift deposits tend to be less valuable than deposits at commercial banks because they yield more, and customers might be quick to leave once those rates disappear.

"For the right price, those branches and deposits are valuable, probably to someone with a footprint in southern California," he said. "Would a Wells Fargo or a U.S. Bancorp, which are strong and healthy and would want to expand their franchise, look at it? I think so."

Neither bank immediately returned requests for comment.

(Additional reporting by Dan Wilchins; Editing by Martin Golan)