Hewlett-Packard shares plunged 9 5/8, or 13 percent, to 67 Wednesday after a slew of analysts cut their fourth-quarter and fiscal 1999 earnings estimates on concerns that its Unix workstation business was struggling and corporate PC sales were lagging. Although HP didn't make a formal announcement, it did confirm late Wednesday that it had spoken individually to different analysts, telling them that weak North American server sales could weigh on results for the fourth quarter. Earlier this month, CEO Carly Fiorina had said HP had "a decent shot" at meeting the First Call consensus estimate of 98 cents a share in the fourth quarter. She added, however, that it expected total sales growth to be at the low end of the 10 percent to 13 percent range projected by analysts. Since then, however, the company has been unable to make up for the North American sales shortfall through cost cutting and upside in other business areas, as it had hoped. Company officials also said last month's earthquake in Taiwan had disrupted PC production and limited the potential for upside in that business. HP said that PCs were not a problem area but because of the earthquake, that division would not deliver any positive surprises. BancBoston Robertson Stephens analyst Dan Niles cut his fourth-quarter estimate from 82 cents a share to 73 cents a share and slashed his fiscal 2000 estimates from $3.30 a share to $3.20 a share. Niles also expects HP's fourth-quarter sales growth to be closer to 7 percent. "We believe UNIX is having major issues in the quarter," Niles said in a research note, adding that the company is still having sales force problems and some Y2K issues are starting to develop. He also forecast that HP's PC business, which grew 28 percent in the July quarter, will likely grow in the mid-single digits in the October quarter, around five percent. "Consumer demand is great, but corporate desktop demand is horrible," Niles said. "My suspicion is that it's year-2000 related. We believe Q1 will also be challenging." Niles wasn't the only analyst chopping away at HP's earnings estimates. Gruntal & Co. reduced its fourth-quarter estimate from 77 cents a share to 70 cents while Merrill Lynch chopped it from 78 cents to 73 cents, respectively. All this comes just a few months after HP rolled past analysts' estimates in its second quarter, earning $853m (£511m), or 85 cents a share, on sales of $12.2bn. Its shares moved up to a 52-week high of 118 7/16 in July after trading at a low of 56 3/4 last October. Interestingly, 16 of the 28 analysts following the stock rate it either a "buy" or "strong buy" while the remaining 12 analysts are calling it a "hold". Reuters contributed to this report. What do you think? Tell the Mailroom . See techTrader for more technology investment news, plus quotes and research.