Apple Computer's fourth quarter profit warning sent the stock plunging 47 percent Friday morning. Apple's freefall also dinged other PC makers. Apple was off 25.50 at 28 in morning trading. In the first 15 minutes of trading more than 26 million shares exchanged hands. Apple said Thursday that it will report sales of between $1.85bn to $1.9bn, just slightly better than $1.83bn it recorded in what most analysts considered a disappointing third quarter. Earnings will be between 30 cents to 33 cents a share in the quarter, well below the First Call consensus estimate of 45 cents a share. Analysts handed out a round of downgrades on the news. Bear Stearns downgraded the stock from "buy" to "neutral", SG Cowen cut it from "buy" from "strong buy", Paine Webber dropped it from "attractive" to "neutral", Morgan Stanley cut it from "outperform" to "neutral", and Banc of America lowered it from "strong buy" to "market perform". And Lehman Brothers cut earnings estimates for fiscal 2000 from $1.84 to $1.71. Bear Stearns analyst Andrew Neff slashed ratings on several PC makers, cutting Apple, Dell, and Gateway from "buy" to "neutral", and Compaq and Hewlett-Packard from "buy" to "attractive". In a research note, Neff said the concerns were prompted by more than just Apple. "Our concern relates to the multiple negative data from industry Intel, Apple, Lexmark, SCI, cell phones, telecom spending, weaker component prices, etc. and macro-economic [currency, oil, slowing growth] issues," he wrote. Other analysts disagreed with that theory, stating that Apple's problems were fairly concentrated. "In our opinion, investors should not read this Apple blow-up as evidence that PC demand is weak," Merrill Lynch's Steve Fortuna wrote in a research note. "Apple is, in many ways, a market unto itself. We believe there is a high likelihood that investors will overreact to this news and take down the PC names in sympathy." They certainly did with regard to at least one PC makers. Dell slipped 1.56 in sympathy, but Compaq rose 0.85 to 29.10. In what chief executive Steve Jobs termed a "speedbump" the company cited weak sales of its Power Mac G4 cube PCs as well as sluggish sales in all geographies and in its education business, as reasons behind the shortfall. But analysts said the news was more than just a bump in the road. "Overall consumer demand doesn't appear to be as low as Apple's numbers indicate," Sanford Bernstein analyst Vadim Zlotnikov said. "It looks like sales of its G4 cubes haven't taken off they way they expected. At least so far." Larry Barrett, ZDII, and Reuters contributed to this story. See ZDII for US tech investor news. See techTrader for more technology investment news, plus quotes and research. To have your say online click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.