Tesla chief Elon Musk has taken a 9.2% stake in microblogging site Twitter, possibly making him the biggest shareholder in the company, Reuters reported on Monday.

Musk now owns 73.5 million shares in Twitter, taking his passive stake in the company to $2.9 billion, or about Rs 218.99 billion, according to filings with the United States Securities and Exchange Commission.

A passive stake is one in which the shareholder does not play an active role in running a company.

The Tesla CEO now holds a stake in Twitter that is over four times larger than that of the social media platform’s founder Jack Dorsey, according to The Guardian. Dorsey holds a 2.25% stake in Twitter.

After the news broke out, Twitter shares increased by 26% in pre-market trading.

Daniel Ives and John Katsingris, analysts with United States-based investment firm Wedbush, said that the passive stake could be “just the start of broader conversations with the Twitter board/management that could ultimately lead to an active stake and a potential more aggressive ownership role of Twitter”, according to AFP.

Musk, the world’s richest man, is very active on Twitter and has more than 80 million followers on the platform.

On March 25, he had launched a poll asking people if they believe Twitter rigorously adheres to the principle of free speech, to which 70.4% respondents answered in the negative. On the next day, he hinted at launching his own social media platform.

“Given that Twitter serves as the de facto public town square, failing to adhere to free speech principles fundamentally undermines democracy,” he had said. “What should be done? Is a new platform needed?”