An unexplained computer glitch caused a one-day delay in posting an estimated $2 billion in transactions at First Interstate Bank of California last week, bank officials disclosed Wednesday.
The data processing problem was discovered last Thursday night and was corrected in time to avoid any widespread effect on customer accounts, two bank executives said.
The quick resolution probably averted a major embarrassment for the bank in which huge numbers of customer checks could have bounced because deposits were not recorded.
"We did not have a disaster," said Charles J. Buchta, an executive vice president at the Los Angeles-based bank. "We had a systems problem that we are still diagnosing to make sure it doesn't happen again."
The problem affected all checking account transactions last Thursday--3 million to 4 million transactions, both deposits and checks or other withdrawals. While precise figures were unavailable, officials estimated that $1 billion in deposits was not recorded, and a roughly equal amount in checks and other debits was not deducted from accounts.
Because neither deposits nor debits were recorded, bank officials said the number of accounts in which a check bounced because a deposit was not counted should have been minimal.
"We can't say that no checks were bounced, but I would say there were darn few," Buchta said.
Robert Campbell, a bank spokesman, said there had been no abnormal level of reports of customer complaints as a result of the glitch.
The problem was discovered at 10:30 p.m. last Thursday as the entire record of the day's transactions from the bank's branches was being posted through a computer at the bank's back office center at 1200 West 7th St. For unexplained reasons, the posting was rejected by the computer.
Buchta said data processing employees worked on the problem all night and the following day, and the transactions were finally posted late Friday afternoon. Friday's transactions were recorded on time, he said.
John A. Miller, a senior vice president at First Interstate Services, the subsidiary that handles data processing for the bank and its affiliates, said the system is still being studied to determine the cause of the problem. The transactions of affiliated banks were not affected.
"We're doing a post-mortem to analyze the problem and take corrective action to ensure that it doesn't happen again," Miller said.