Verizon Communications says it estimates fourth-quarter and 2009 profit below Wall Street forecasts.

The company said new subscribers and those upgrading phones accounted for a higher proportion of its overall customer base than in the previous quarter, which lowered its profit margin in the latest quarter. Meanwhile, its traditional phone business continued to erode.

At an investor conference Wednesday, Verizon CEO Ivan Seidenberg said the company expects fourth-quarter earnings of 53 cents to 55 cents per share excluding special items. For the full year, it expects income of $2.39 to $2.41 per share.

Analysts polled by Thomson Reuters predict earnings of 58 cents per share for the quarter and $2.44 per share for the full year.

Shares of Verizon, the second-largest phone company in the U.S., were down 8 cents to $31.65 in afternoon trading Friday.