Updated from Jan. 8Sprint ( S) tumbled 9% early Tuesday after the struggling wireless giant detailed its latest quarterly subscriber losses and set plans to cut 5,000 jobs. The Reston, Va., telco said it lost 306,000 postpaid subscribers in the quarter ended Dec. 31. The company, which is the sole big wireless operation losing subscribers amid a red-hot streak for the industry, also guided to 2007 revenue at the low end of Wall Street's expectations. Sprint said it would reduce its overall full-time head count by 5,000 from the 2006 year-end level of 64,600, in a bid to streamline its cost structure. Sprint said a lower-margin revenue mix, investment of an additional $1.1 billion in business operations and start-up costs associated with the build-out of a so-called WiMax wireless network "will pressure profitability" in the near term. Shares fell $1.75 to $17.89 early Tuesday. Sprint was downgraded at Credit Suisse, Deutsche Securities and CIBC, while RBC and Prudential cut ratings on wireless rival Alltel ( AT). The news comes after a turbulent year that saw three of Sprint's top executives bail in the aftermath of Sprint's acquisition of Nextel. The departures leave CEO Gary Forsee unchallenged atop the company. Sprint says preliminary sales for the year were $41 billion, which is below the $41.5 billion analysts were looking for, according to Reuters Research. Looking ahead, the company expects 2007 sales to be flat at between $41 billion and $42 billion. Wall Street had been looking for $42 billion in sales this year.