Twitter shares are climbing Monday amid reports a big investor is looking for big changes at the top.
Sources tell Reuters hedge fund Elliott Management has taken a stake in the social media company.
And they say the activist fund founded by billionaire Paul Singer wants to remove CEO Jack Dorsey.
Dorsey is vulnerable to outside pressure because he only owns 2% of the company, and Twitter has granted shareholders equal voting rights.
It's one of the few tech companies STILL headed by one of its founders.
He surprised Wall Street last November when he said he wants to move to Africa for up to six months. That raised questions about his management.
And he's got more than Twitter on his plate: Dorsey's also the CEO of mobile-payment company Square.
Twitter shares tumbled last year when the platform experienced technical glitches that hindered its ability to target ads and share data with partners. What's more, the company has limited scale because it hasn't expanded beyond its core micro blogging platform.
Twitter shares rose sharply Monday morning on news of Elliott's stake.