Updated from 12:50 p.m. ESTShares of telecom giant Verizon ( VZ) fell Tuesday, as investors digested the reality of the firm's fourth-quarter results. Verizon's shares slipped $1.03, or 3.3%, to $29.96, reversing a broader stock market rally that saw the Dow and the Nasdaq increase 0.72% and 1.04%, respectively. Even after posting a 15% hike in its fourth-quarter profit, and reporting healthy revenue, the firm's results suggest that there are plenty of challenges in store for Verizon. Whereas Verizon's wireless business grew 12.3% year over year to $12.8 billion, its wireline operation was a different story. The company's total wireline revenues, for example, slipped 2.7% to $11.9 billion, prompting at least one analyst to voice his concern. "With all the focus on wireless, perhaps it's time for the debate to shift back to the wireline business," wrote Craig Moffet, a senior analyst at Bernstein Research, in a note released Tuesday. "Overall wireline revenues declined a surprisingly sharp percentage versus a year ago." The analyst added that Verizon's wireline margins also dropped by 300 basis points to just 24.5%, a much worse showing than he had expected. Verizon's enterprise wireline revenues also took a hit during the fourth quarter, casting something of a cloud over the firm's 2009 prospects. "Enterprise results, inarguably the most cyclically exposed part of the portfolio, were perhaps the biggest story of the quarter," wrote Moffet. "Verizon's year-over-year decline of 2.2% versus our forecast of 1% suggests that things could get much worse in 2009."