Elon Musk has become the largest shareholder in Twitter

Elon Musk has purchased a 9.2 percent stake in Twitter Inc., making him the platform’s largest shareholder, just a week after hinting that he might shake up the social media industry.

Twitter shares rose about 26% in premarket trading following the regulatory filing detailing Musk’s purchase of the holding on Monday.

Musk, 50, polled his more than 80 million Twitter followers last month, asking if the company adheres to free speech principles.