Jon Swartz

USA TODAY

SAN FRANCISCO — A senior Verizon executive who was instrumental in the telecom company's planned $4.8 billion purchase of Yahoo's Internet business expressed doubts on Thursday over the deal, the second top exec to raise the specter of a changed or abandoned takeover.

"I can't sit here today and say with confidence one way or another because we still don't know," Marni Walden, president of product innovation and new businesses at Verizon, said when asked about determining whether the deal gets done. She did, however, tell attendees at an investment bank conference in Las Vegas that the deal made sense.

Yahoo (YHOO) shares rose 3%.

Walden's comments echo concerns of Verizon's general counsel, who questioned the acquisition's price tag because of a massive computer breach that compromised 500 million Yahoo customers. (Yahoo has since disclosed another breach, this time affecting more than 1 billion customers.)

Yahoo had no comment on Walden's statement. "We are confident in Yahoo’s value and we continue to work towards integration with Verizon," a Yahoo spokeswoman said.

Verizon declined further comment.

If Yahoo's security breaches have cast doubt on its mega-deal with Verizon and the future of an Internet icon, comments from Verizon executives have only exacerbated matters. Bloomberg, citing people familiar with the matter, last month reported Verizon is reconsidering the deal, or could bargain down the price.

"I think we have a reasonable basis to believe right now that the impact is material and we're looking to Yahoo to demonstrate to us the full impact," Craig Silliman told reporters at a Verizon event in Washington, D.C., in October. "If they believe that it's not, then they'll need to show us that."

Hacking woes aside, Verizon inherits a company being clobbered by larger competitors in the $229 billion global market for digital ads.

Yahoo corralled $2.98 billion in digital advertising revenue last year — good for 1.5% of the market — but it lagged far behind rivals Google ($63.1 billion; 32.4%), Facebook ($25.9 billion; 13.3%) and Alibaba ($12.7 billion; 4.6%), according to eMarketer.

The numbers are likely to worsen in 2017. Yahoo's ad revenue will rise slightly to $3 billion, but its market share will erode to 1.3% — losing further ground to Google ($72.7 billion; 31.7%), Facebook ($33.8 billion; 14.7%) and Alibaba ($18.1 billion; 7.9%), eMarketer predicts.

Follow USA TODAY San Francisco Bureau Chief Jon Swartz @jswartz on Twitter.