Elon Musk now owns a sizable chunk of Twitter. 

The Tesla chief took a 9.2% stake in the social media site on March 14, according to a Securities and Exchange Commission filing. The stock purchase makes Musk the social network's biggest shareholder, Bloomberg reported Monday.

The shares are worth $2.89 billion, based on Twitter's closing price Friday, according to CNBC. Twitter's stock soared more than 27% on Monday, closing at $49.97.

Musk is among Twitter's most prolific users and has used his reach to question the platform's commitment to free expression. On March 25, he polled his 80.2 million followers, asking if they thought Twitter "rigorously adheres" to the principle of free speech. More than 70% said no. 

Musk was referring to free speech protections under the First Amendment to the US Constitution, though that only applies to government censorship of speech. Twitter, as a company, determines what can be posted on its platforms, requires users to agree to terms of service when they sign up and can remove people who break its rules.

On March 26, Musk followed by asking if a new platform is needed and telling a follower that he is "giving serious thought" to starting one. The post came nearly two weeks after the date on the SEC filing for his stake in Twitter.

It's unclear what Musk's intentions with Twitter are, but his stake in the company could impact its long-term strategy. 

"Specifically, Musk could seek to influence the openness of the platform and how it controls content or push to invest in the subscription model more aggressively," Ali Mogharabi, a senior equity analyst for Morningstar, said in a note on Monday. Last year, Twitter started rolling out a new $3 per month subscription service called Twitter Blue that allows people to undo tweets, read ad-free articles and get access to other features.

Twitter has been undergoing major leadership changes. In November, Twitter co-founder Jack Dorsey stepped down as the company's chief executive. Parag Agrawal, who was previously Twitter's chief technology officer, took over the executive role. Twitter reported $5 billion in annual revenue in 2021 and currently has 217 million daily users who currently see ads. Twitter has a goal of reaching at least $7.5 billion in annual revenue and 315 million users in 2023.

Musk has a large following on Twitter but some of his tweets have landed him in hot water. Musk got into a legal battle with the SEC in 2018 when he told his then-22 million Twitter followers that he was ready to take Tesla private. The regulator sued Musk for "false and misleading" statements to the electric car company's investors. 

They reached a settlement that saw Musk and Tesla each paying $20 million and gave SEC oversight over some of Musk's social media posts. Since then, Musk's lawyers have argued that the oversight policy has become unworkable and asked a federal judge to end the settlement.

Twitter didn't immediately respond to a request for comment. Following the news Monday about his stake in Twitter, Musk tweeted, "Oh hi lol." Later in the day, he tweeted a question: "Do you want an edit button?"

Do you want an edit button?

— Elon Musk (@elonmusk) April 5, 2022