The nation's thrifts lost $11.1 billion in 1988, 48 percent more than 1987's $5.8 billion loss, and face a triple economic threat in 1989, according to Alex Sheshunoff, a New York-based authority on the financial industry.

While 2,192 S&Ls - 69 percent of the nation's 3,174 S&Ls - earned a profit last year, the industry as a whole ended 1988 with its biggest loss in history. The record loss was concentrated in the Southwest.Thrifts in Texas lost $9.7 billion, followed by Arizona where the loss amounted to $657 million, said Sheshunoff, president of Alex Sheshunoff & Co.

He said 1989 poses additional challenges for thrifts, the three major threats being:

- Rising interest rates on deposits. High rates squeeze the interest spreads of thrifts that hold substantial amounts of fixed-rate mortgages.

- A growing inventory of repossessed real estate. The industry unwillingly owns $25.5 billion - more than half of which is in Texas, with California a distant second - plus massive amounts of foreclosed property are held by government agencies.

- Weakening property values. Real estate values in some regions, particularly the Northeast, appear to be starting to deteriorate.

"Those are three tough challenges," said Sheshunoff. "It's like a three-ring circus. The S&L executive has to juggle, tame lions, and walk a tightrope, all at the same time."

The good news, he said, is that they're working with a net. The bad news is that it's woven out of U.S. tax dollars.

"Moreover, the thrift crisis, even though concentrated in the Southwest, has shaken public trust in thrifts and those who regulate them."

According to a recent consumer survey by his firm, Sheshunoff said 6 percent of Americans have withdrawn money from a thrift because of the industry's problems.

"Thrifts must regain the public trust if they are to stem the outflow of deposits and lower the rates they pay to retain them," he said.