Updated from Jan. 18 The Razr's edge didn't last long at Motorola ( MOT). The wireless giant posted a strong fourth quarter Tuesday, boosted by stronger-than-expected sales of its new high-priced handset, the Razr. But shares sagged as first-quarter guidance failed to impress a jaded Wall Street, which has seen Motorola's up-and-down act before. Early Wednesday, the stock fell $1, or 6%, to $16.43. For its fourth quarter ended Dec. 31, the Schaumburg, Ill., tech giant posted earnings from continuing operations of $687 million, or 28 cents a share. That's up from the year-ago $441 million, or 18 cents a share, and 4 cents ahead of the Wall Street analyst consensus estimate. Revenue jumped 27% from a year ago to $8.84 billion, easily besting the $8.46 billion Thomson First Call consensus. Motorola cited a strong performance in its Personal Communications Segment, where sales surged 51% from a year earlier. Sales of the company's high-end Razr handset "greatly exceeded sales expectations," Motorola said, adding that it shipped 31.8 million handsets and gained 3 points of cellphone market share. "They blew the doors off on handsets," says Charter Equity analyst Ed Snyder, who rates Motorola buy and was looking for fourth-quarter sales of about 27.5 million units. "I think the Razr phone did better than many people expected." Motorola says the robust quarter will let it retake the No. 2 position in handset sales that it briefly lost to Samsung last quarter. The numbers, which are Motorola's alone and haven't been confirmed by any third-party researcher, would leave it behind only leader Nokia ( NOK). Some investors had expected Motorola to produce strong numbers, but they thought that Samsung's middling numbers in the latest quarter suggested that growing competition could take a chunk out of Motorola's handset market share. Motorola seems to have put those fears to rest with Tuesday's numbers, which suggested the pricey Razr phone is doing just what Motorola wants -- pushing the market upscale.