Twitter is reportedly being targeted by an activist shareholder seeking to replace Jack Dorsey

Bloombergwas the first to report the news, which was then confirmed byReuters.

Elliott has nominated four directors to Twitter's board in an attempt to fill three vacant seats at this year's annual meeting, according to Bloomberg, citing people familiar with the matter.

The New York-based firm, founded by billionaire Paul Singer, is also having "constructive discussions" with Twitter, the report said. Twitter declined to comment. Elliott did not respond to a Saturday request for comment.

It's not clear how big a stake Elliott has in Twitter or who it wants to replace Dorsey with, Reuters and Bloomberg reported.

Many tech companies, like Facebook and Google, issue multiple classes of stock. But Twitteronly issues common stock, giving shareholders equal voting rights, while also leaving the company more vulnerable to activist shareholders who can buy up a large amount of shares. While Jack Dorsey leads Twitter, he only owns a small percentage of the company's shares.

Twitterturned its firstannual profit in 2018, but it still suffered from a declining user base. The social media network has been slower than its rivals like Facebook and Snapchat at expanding new features. Ina 2018 interview with CNN Business,Dorsey said "we're ready to question everything" about the social networking site as it sought to quell criticism over spam, abuse and misinformation.

Elliott is widely viewed as one of the most successful activist investors, a type of investment firm that aims to persuade management teams to make sweeping changes aimed at reviving stock prices.

In early February, Elliott revealed that it built a "substantial" stake in SoftBank, the firm run by billionaire Masa Son, and had held private talks with the company. SoftBank recently attracted scrutiny for its investments in WeWork, Uber anddog walking startup Wag.

TheSoftBankcampaign is the biggest move by Elliott since itsinvestment last yearin AT&T (T). (AT&T owns CNN's parent company WarnerMedia.) AT&T and Elliott reached a truce last October that included a pledge by the company not to make any major acquisitions.