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Tesla shares jump after Elon Musk tweet

It was just a tweet.

Monday at 9:35 a.m. Tesla Motors founder and CEO Elon Musk sent out a titillating tweet saying that, in a few days, he was planning to say something.

He teased that at a press conference on Thursday he would be announcing something that would "end range anxiety" with a software update to the company's highly rated Model S electric sedans.

The speculation began. Will it be a change that would actually stretch the car's range? Or an improved reporting system that will help alleviate the stress of running out of battery? Either way, the market was buying it. Tesla (TSLA) stock immediately shot upward.

And that prompted another tweet later in the day, this time a defensive assertion that, no, the first tweet was not intended to drive stock prices up:

By the end of trading Monday, Tesla's stock price had risen from $191.10 a share at tweet time, to $195.70 at the closing bell.

It seems this whole range anxiety thing has turned into tweet anxiety. Late Monday night Musk sent out a tweet celebrating the apparent success of his battery-swapping program along the California coast. He quickly added:

"But that's not what I mean by addressing range anxiety."

  • Amanda Schupak

    Amanda Schupak is the science and technology editor at CBSNews.com