Update: Steve Ballmer confirmed to Bloomberg that he has indeed taken a 4% stake in Twitter. No hack and no prank. Following that confirmation, shares of Twitter shot upward suddenly. They were up 1.21% at $30.08 per share and still rising, as of this writing.

Previously:

Twitter may have received a huge vote of confidence (well, perhaps) from former Microsoft CEO Steve Ballmer. A tweet this morning from an unverified account claiming to be Ballmer’s new account indicates that he has grabbed up a 4% stake in the microblogging platform over the last “few months.” A 4% stake would be worth approximately $800 million.

Steve Ballmer Bought 4% Stake In Twitter Inc (TWTR) [UPDATED]

Steve Ballmer said to have 4% stake in Twitter

Tweets from the account @clippersteveb (his verified account) suggest that Ballmer is moving to a new account @Steven_Ballmer:

This other Steve Ballmer account has not been verified, so there’s a lot of skepticism about whether he really has invested in Twitter, both on Twitter and in the media. Some are speculating that he may have been hacked or that there’s a prank going on here.

Real or a hack?

However, a tweet from the old account on Oct. 1 suggests that the tweet on the new account could be genuine—unless, of course, someone hacked that old account, which is entirely possible. There have been plenty of cases in which hackers compromised the Twitter accounts of high-profile companies, so it’s possible that this has happened again.

Business Insider makes a good case for why the new Twitter account isn’t real. There are multiple tweets on the account claiming that it’s real, and it certainly is doubtful that Ballmer would feel the need to keep telling his followers that his new account is real. Plus, it seems like two weeks would be enough time for him to get the new account verified with

Twitter. And anyway, why wouldn’t Ballmer just change the handle on his account rather than create a new one? Changing the user handle does result in the “Verified” badge disappearing from the account temporarily, but it still seems like a better alternative than creating a new one.

Why would Ballmer buy Twitter?

Indeed, Twitter’s performance since it went public has been less than compelling. The company has repeatedly disappointed on user growth, but Ballmer’s tweet, if real, suggests that he believes all of the recent changes, including the appointment of co-founder Jack Dorsey as permanent CEO, will finally put the company on the right track.

At any rate, it doesn’t seem like Wall Street is taking the tweets too seriously this morning. Either they don’t believe the tweets are genuine, or perhaps they just think Ballmer is nuts. As of this writing, shares of Twitter were down 0.24% at $29.64 per share.

Of course Ballmer wouldn’t be the first high-profile investor Twitter has attracted recently. Saudi Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud recently upped his stake to 5.17%.

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