The recent failure of Sogo Co. has revived a nightmare for major Japanese banks whose share prices are falling to levels that bring to mind early 1999 and the country's acute financial crisis.

That's because the department store operator's filing for court protection earlier this month has brought renewed scrutiny to banks' bad-loan problems.

Market players fear that many other ailing firms may follow the same path as Sogo. If that proves to be the case, it will add a further burden atop the massive bad loans already weighing on banks.