Tesla CEO Elon Musk has taken a 9% stake in Twitter to become its largest shareholder after raising questions about the social media platform's dedication to free speech.

The regulatory filing Monday describes Musk as a long-term investor looking to minimize his buying and selling of the shares.

He has also pondered starting a rival social media network, and industry analysts are skeptical about whether the mercurial CEO would remain on the sidelines for long.

Musk told his 80M followers on Twitter that he was " giving serious thought " to creating his own social media platform and has clashed repeatedly with financial regulators about his use of Twitter.

Some Twitter employees and experts fear Musk’s involvement could also push the company further into chaos after years of investor activism and the sudden departure of former CEO Jack Dorsey.