(NewsNation) — Twitter’s future is in flux amid billionaire and entrepreneur Elon Musk’s bid to buy the tech giant.

Twitter revealed in a securities filing last week that Musk has offered to buy the company outright for more than $43 billion and take the social media company private. But Musk is far from the first person to propose making a publicly traded company into a privately held one.

In 2018 alone, there were more than $54 billion worth of deals that took publicly traded companies private. Some of the most infamous deals over the past few decades involve high-profile companies like Dell and Burger King.

Burger King originally went public in 2006 but then was taken private in 2010 by a private equity firm in a deal worth $3.26 billion. Burger King became a public company again in 2012.

Dell Computers was taken private in 2013 amid financial struggles by the corporation’s foundation in a partnership with a private equity firm. Dell was relisted publicly in 2018. The strategy increased Dell’s value by at least $4 billion and the company’s founder said it allowed him to transfer the company.

Twitter is far from the only major tech company to be potentially taken private. The online hosting service Cloudera was just taken private in a $5.3 billion deal.

But Musk’s goal of owning Twitter slipped further out of his reach Friday.

Twitter said last week that its board of directors unanimously adopted a “poison pill” defense in response to Musk’s proposal to buy the company. The move would allow existing Twitter shareholders — except for Musk — to buy additional shares at a discount, thereby diluting Musk’s stake in the company and making it harder for him to corral a majority of shareholder votes in favor of the acquisition.

The billionaire has been a vocal critic of Twitter, mostly over his stated belief that it falls short on free-speech principles. Musk has described himself as a “free-speech absolutist” but is also known for blocking other Twitter users who question or disagree with him.