Elon Musk announced on Friday he was terminating his $44 billion (€43.2 billion) deal to buy Twitter, saying "multiple provisions" of the agreement had been breached.
The world's richest man wrote in a regulatory filing that the social media company had failed to provide information about fake or spam accounts on its platform.
The terms of the deal require Musk to pay a $1 billion (€981 million) break-up fee if he does not complete the transaction. But Twitter is already saying it will fight in court to enforce it.
The news is the latest twist in a weeks-long will-he-won't-he saga that saw the billionaire CEO of Tesla and SpaceX publicly accuse Twitter of underestimating the numbers of fake or spam accounts, which are key to the company's business performance.
In a letter to the Securities and Exchange Commission, Musk said Twitter had “not complied with its contractual obligations” surrounding the deal, namely giving him enough information to “make an independent assessment of the prevalence of fake or spam accounts on Twitter’s platform”.
Much of the takeover drama has played out on Twitter, with Musk - who has more than 95 million followers - also repeatedly lamenting that the company was failing to live up to its potential as a platform for free speech.