The latest in a string of reports raising the possibility of accounting issues at International Business Machines Corp. drove the computer maker's stock down more than 4 percent, a large move for the blue-chip company.

The New York Times on Friday reported that the Armonk, New York-based computer maker hadn't disclosed a $300 million gain on the sale of an optical unit, but that it was this gain that enabled the company to meet fourth-quarter earnings estimates.

IBM spokeswoman Carol Makovich said that IBM had adequately disclosed the sale of the unit through two press releases from Canada's JDS Uniphase Corp. , which purchased the unit for $340 million in cash and stock in December. 

"IBM's accounting is conservative and fully compliant with all regulatory standards," Makovich said. 

Gary Helmig, an analyst at Soundview Technology, said that IBM has been taking shots for years regarding specific items but that Louis Gerstner was operating under the belief that a lot of the details aren't important. IBM is so large it can't make everything visible, he said. 

But investors who have watched stocks like Enron Corp. and Tyco International Ltd. drop on accounting-related concerns, are bailing, he said. 

"I think you have people who just do not want to own stocks where there is any question at all -- whether it's founded or unfounded -- of impropriety, and therefore you right now have those people selling the stock," Helmig said. 

IBM shares were off 4 percent, or $4.62, at $103.27 in morning New York Stock Exchange trading. By comparison, the American Stock Exchange Hardware index was off only 1.4 percent.