Another scandal, revealed by a whistleblower, has hit already-embattled Toshiba Corp., further eroding the market credibility of its corporate governance.

At noon Tuesday, the 140-year-old company, which has been working to put an accounting scandal behind it, missed a deadline to release an earnings report for the April to December period, citing alleged "inappropriate pressure" at its U.S. unit over the purchase of another American firm.

In an extremely rare move, Toshiba later released its unaudited estimates of earnings for the nine months through December and its full-year outlook at 5:10 p.m., stunning market participants.