Walden, executive vice president and president of global media, also said at a Fortune conference in Washington that her planned departure, announced last week, had nothing to do with Verizon's earlier announcement that a data breach at Yahoo affected 3 billion accounts, three times what the company said in December.

"I am going to take a risk and I am going to go do something different," she said.

In a brief interview after the event, Walden said she did not have another job lined up. She has a one-year non compete, she noted, which she joked will require her to take a "forced vacation."

Walden, the company’s top-ranking female executive, played a big role in Verizon’s acquisition of Yahoo and its merger with AOL to create the Oath unit. The plan for Oath, she said, "is to be a relevant third player in this space" and be a "relevant player" in the advertising market.

Walden, who was seen as a potential successor to Chief Executive Lowell McAdam, will move into a strategic adviser role​ from Dec. 31, until her departure in February 2018.

Yahoo said last week that all 3 billion of its user accounts were hacked in a 2013 data theft. Walden defended the company's due diligence review of the Yahoo purchase and noted the company ultimately paid $350 million less than initially announced for Yahoo's core assets.

Walden most recently spearheaded Verizon’s entry into global digital media and telematics.

Hans Vestberg, the former chief executive of Ericsson, who joined Verizon earlier this year, and John Stratton, head of the company’s customer and product operations team, are also seen as potential successors to McAdam.  

(Reporting by David Shepardson; Editing by Steve Orlofsky)

By David Shepardson