https://arstechnica.com/tech-policy/2022/04/elon-musk-buys-9-of-twitter-stock-as-he-pressures-company-on-free-speech/

Elon Musk has purchased 9.2 percent of Twitter's stock, he revealed in a Securities and Exchange Commission filing on Monday. The Tesla and SpaceX CEO bought 73,486,938 Twitter shares on March 14, the filing said.

Musk's stake was worth $2.89 billion, based on Twitter's closing price on Friday, and "appears to make Mr. Musk Twitter's largest shareholder," The New York Times wrote. Musk's "holding is slightly larger than Vanguard's 8.8 percent at the end of last year, and it dwarfs the 2.3 percent stake of Jack Dorsey, Twitter's former chief executive."