STORY: Musk said he was terminating the deal because the social media company had breached multiple provisions of the merger agreement.
Twitter's chairman, Bret Taylor said the board planned to pursue legal action to enforce the merger agreement.
In a filing, Musk's lawyers said Twitter had failed or refused to respond to multiple requests for information on fake or spam accounts on the platform, which is fundamental to the company's business performance.
Boston College Law School professor Brian Quinn said those arguments were unlikely to be successful in court.
"Those are going to be hard arguments to make. So he's going to bear a burden in court to prove to the judge that these are going to be sufficient for him to walk away," he said.
Musk also said he was walking away because Twitter fired high-ranking executives and one-third of the talent acquisition team, breaching Twitter's obligation to "preserve substantially intact the material components of its current business organization."
Musk's decision is likely to result in a protracted legal tussle between the billionaire and the 16-year-old San Francisco-based company.
"This is going to be a Game of Thrones court battle between Musk and the Twitter board," said Ives.