Just a week after reporting fourth-quarter earnings,


(VZ) - Get Report

CFO Doreen Toben says she will retire by mid-year 2009.

Toben had been Verizon's finance chief since 2002, and a replacement is expected to be named soon.

The move comes amid mixed financial performance under challenging economic conditions and heated competition with cable rivals like

Time Warner Cable





. Verizon reported solid wireless results last week, but its core phone line business

eroded more than expected

and its service to businesses suffered a surprising decline.

"I have had the good fortune of working with what I consider to be the best financial team in business today, as well as Verizon's superb senior leadership," Toben said in a press release. "I feel very good about how this company has transformed itself in a few short years to become the industry's premier provider of network-based communications services."

In the same press release, CEO Ivan Seidenberg praised Toben's efforts.

"Doreen's contributions as CFO throughout Verizon's history as a company will make a profound and positive difference for many years to come," Seidenberg said.

Verizon shares remained largely unchanged in post-close trading Thursday.