Now playing: Watch this: Twitter may find a new home with Google or Salesforce

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Is Twitter up for sale?

CNBC reported Friday that, according to sources, Twitter is in talks with several companies and could soon receive a formal bid. Those companies may include Google and Salesforce.

Twitter and Google did not immediately respond to CNET's request for comment. Salesforce declined to comment.

Twitter's fate is often debated as its woes pile up. Monthly active user growth has been essentially flat for the past several quarters. Third-quarter sales missed Wall Street's estimates. Co-founder Jack Dorsey returned as Twitter's CEO about a year ago, but the company hasn't shown the path correction that many investors hoped for. The social network is even facing a lawsuit from a shareholder who accuses the company of making "false and misleading" statements about its growth projections.

News of a possible sale also comes after RBC Capital Markets' analyst Mark Mahaney downgraded Twitter's stock to "underperform" on Thursday. "This change is based on our belief that Twitter's value proposition to advertisers could be waning, based on our recent advertiser survey data," he said in an analyst note. "We note that we still believe Twitter is a unique asset with a strong value proposition to core users."

There's no sale timeline yet. CNBC reported that a deal is not certain but that conversations are "picking up momentum and could result in a deal before year-end."

Twitter's stock is up nearly 19 percent Friday morning, likely due to the rumor.

Even Salesforce's chief digital exec, Vala Ashfar, tweeted about the speculation:

This isn't the first round of Twitter sales rumors, with names like Verizon and IBM popping up in the past. Still, "our attention is piqued," Forrester analyst Erna Alfred Liousas told CNET, because companies including Salesforce and Google are now in the mix.

With 313 million users, Twitter has an engaged user base, she noted. While the social network has hit a few obstacles, including stagnant growth, it has been making traction by doubling down on real-time interactions, live streaming and customer service, she said.

"Acquisition is an option because Twitter is constantly compared to Facebook," she said, noting Facebook's 1.23 billion users vs. Twitter's 313 million. "Ad dollars are on the line, along with marketing and consumer expectations, which means all options are on the table."