Tesla CEO Elon Musk wants the world to know change is coming to Twitter.

Twitter said Monday it has reached a deal with Musk, who will buy Twitter for $54.20 a share in cash, valuing the influential social media site at about $44 billion. The announcement came after Musk rejected a seat on Twitter's board. With a 9.2% stake in Twitter, Musk is one of the company's largest shareholders.

Twitter's deal with Musk has fueled speculation about what this could mean for the social media site's future. The sale initially seemed unlikely, but Twitter's board then reportedly began to take the offer more seriously after Musk revealed more details about how he would finance the potential purchase.

"Free speech is the bedrock of a functioning democracy, and Twitter is the digital town square where matters vital to the future of humanity are debated," Musk said in a statement. "I also want to make Twitter better than ever by enhancing the product with new features, making the algorithms open source to increase trust, defeating the spam bots, and authenticating all humans. Twitter has tremendous potential -- I look forward to working with the company and the community of users to unlock it."