Dropbox (DBX) - Get Report is having one heck of a Thursday. 

Shares of the data storage and file sharing company exploded as much as 18% on high volume, despite a lack of news. Dropbox declined to comment on the stock's move. Shares finished the day up 14% to $36.12.

But with Dropbox's compelling business model, one can't rule out a possible deal brewing. After all, Salesforce.com Inc. (CRM) - Get Report owns 6.45% of Dropbox according to Factset data.

Morningstar Analyst William Fitzsimmons told TheStreet that he was "a little perplexed" by the rally Thursday, but noted that many names that have held initial public offerings since the start of 2018 were climbing Thursday, including Zscaler Inc. (ZS) - Get Report and Smartsheet Inc. (SMAR) - Get Report .

"There is a palpable appetite in the U.S. market for new IPOs given the overall consolidation and aggressive M&A activity in the U.S. market," Fitzsimmons said. "A lot of names like DBX, Zscaler, Docusign Inc. (DOCU) - Get Report , and Zuora Inc. (ZUO) - Get Report had solid earnings after debuting on exchanges, so I would speculate that the rally might be a delayed reaction to the solid first quarter as a public company that these firms produced as well."

But Fitzsimmons offered a kicker: "Dropbox's rally looks outsized compared to these players though, so it would not be outside the realm of possibility that there is a pending announcement or piece of news that we do not know yet," he said.

D.A. Davidson Analyst Rishi Jaluria pointed out that he hadn't heard anything from the company, but that management is not on the road at the moment.

Canaccord Genuity Analyst Richard Davis said, "Best guess is that investors are finally listening to my suggestion that they buy this stock. Up to today, they have been tone deaf and refused to listen."

"If you look at the trading volume, it is likely that someone is buying," Davis said. "DBX and Microsoft Corp. (MSFT) - Get Report have remained among our favorite large cap stocks."

Watch what Dropbox chief operating officer Dennis Woodside told TheStreet back in March right after the company's well-received IPO. 

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