NEW YORK (REUTERS) - Twitter Inc has initiated talks with several technology companies to explore selling itself, a person familiar with the matter said on Friday (Sept 23), signalling the start of what is likely to be a slow-rolling auction of the high-profile but money-losing social media company.

A sale of Twitter has been the subject of on-again, off-again rumours for many months as the company grapples with stagnant user growth, soft advertising sales and losses running at hundreds of millions of dollars a year.

The company's business struggles have come even as the 10-year-old service has evolved into a global source of news, entertainment and social commentary.

Analysts have long considered Alphabet's Google the most likely buyer for Twitter, and a source told Reuters that Salesforce.com is also in pursuit.

CNBC, citing anonymous sources, reported on Friday that Twitter is in talks with companies including Google and Salesforce and may receive a formal bid soon.

Twitter and Alphabet did not respond to a request for comment. Salesforce declined to comment.

Verizon, another company mentioned in media reports on Friday as a possible suitor, said it did not comment on M&A rumours but that it had not submitted a bid for the company.

Twitter shares jumped more than 19 per cent to US$22.22 a share on Friday, marking the largest one-day rise since their first day of trading in 2013. The company now has a market value of around US$16 billion (S$21 billion).

Morningstar analyst Ali Mogharabi said Alphabet would be the best acquirer for Twitter since it has not yet been able to crack social media on its own despite several efforts.

"From a strategic standpoint, we think it would be more beneficial for Alphabet as opposed to Salesforce," Mogharabi said. Former Google executive Omid Kordestani is executive chairman of Twitter.

Morningstar estimates Twitter could be bought for $22 per share.

RIVALS ASCEND

Twitter missed Wall Street's sales expectations in both the first and second quarters of 2016, according to Thomson Reuters StarMine, and has yet to produce a net profit in 11 quarters as a public company. As of the end of the second quarter, the company had an accumulated loss of nearly US$2.3 billion since its inception.

It has also failed to keep pace with rivals, notably Facebook's Instagram and Snapchat. Both now boast more users than Twitter by most measures even though they are much newer, and advertisers have begun to migrate their ad dollars accordingly.

Twitter's revenue grew rapidly under former chief executive Dick Costolo, but stagnant user growth and mounting complaints about lack of innovation in the product led to Costolo's departure last year.

The company has also faced criticism for its failure to stem abuse on the platform and for missing the opportunity to play a bigger role in the red-hot messaging arena. Twitter has 313 million monthly users, up just 3 per cent from a year ago.

Co-founder Jack Dorsey returned to the company as chief executive in 2015 while retaining his role as CEO of payment company Square, and his plan for reviving Twitter is at best seen as unfinished. Recent moves to be a big player in live video, including a deal to broadcast NFL games, are too new to be reflected in user growth or ad sales.

SALESFORCE SURPRISE

The most unexpected development on Friday was Salesforce.com's interest in acquiring Twitter. Salesforce serves business customers with cloud-based computing services and has virtually no presence in consumer media.

But a recent presentation about its new "Einstein"artificial intelligence platform provided a peak at how Twitter could fit into the company's strategy .

Salesforce executives said they license the Twitter"firehose" of all Tweets that come through the platform, and use it to power sentiment analysis and other tools that show how companies and brands are being discussed and perceived.

Salesforce CEO Marc Benioff is active in political causes in San Francisco and two companies are located just blocks from each other in the city.

Salesforce's chief digital evangelist, Vala Afshar, tweeted on Friday: "Why @twitter? 1 personal learning network 2 the best realtime, context rich news 3 democratize intelligence 4 great place to promote others."

Later, Afshar added: "I have tweeted my personal views regarding 'Why Twitter?' numerous times over the past couple of years. I simply love Twitter."

Twitter went public in November 2013 at US$26 a share. The shares peaked above US$74 just over a month after its IPO, but have been on steady downward trajectory since. From then through Thursday's close at US$18.63, the stock had lost three-quarters of its value.

In early September reports swirled that Twitter's board was weighing ways to cut costs, ramp up revenue or possibly maximize shareholder value by selling itself.