From Automotive NewsDetroit, Michigan-General Motors said its fourth-quarter net loss mushroomed to $4800 million as it struggled with high costs, shrinking market share and sluggish sales of sport utility vehicles, according to a 26 Jan. report from Automotive News, a sister publication to Urethanes Technology.The world's largest carmaker said the loss amounted to $8.45 a share, compared with a year-earlier loss of $99 million, or 18 cents a share.Excluding one-time items, the company lost $1200 million, or $2.09 a share. On that basis, analysts' average forecast was a loss of 12 cents a share, according to Reuters Estimates.GM shares dropped 2.7 percent to $23.20 in pre-market trade on the Inet electronic brokerage system, down from a close at $23.85 on the New York Stock Exchange on Wednesday.One-time items reduced earnings by $3600 million, or $6.36 a share. They included a restructuring charge of $1300 million at GM's North American operations, and a preliminary after-tax charge of $2300 million related to a benefit guarantee with the United Auto Workers union and bankrupt auto parts supplier Delphi Corp.Analysts were expecting charges after GM in October announced plans to slash 30 000 jobs and shutter 12 facilities, but no one knew how large the charges would be.Fourth-quarter revenue fell to $51 200 million from $51 400 million a year earlier.The fourth-quarter loss brought GM's net loss for the full year to $8600 million.The carmaker has been facing high labour and raw material costs, loss of market share to foreign rivals, and disappointing sales of high-profit SUVs.GM has seen its debt rating cut to below 'junk' status several times in the past year, by agencies such as Moody's and Standard & Poor's.The carmaker plans to sell a controlling stake in its finance arm, GMAC, in order to restore the unit's investment-grade ratings."