Billionaire Elon Musk has offered to buy Twitter for about $US43 billion ($58 billion), just days after rejecting a seat on the social media company's board.
Mr Musk's offer price of $US54.20 ($72.87) per share was disclosed in a regulatory filing on Thursday.
It represents a 38 per cent premium to Twitter's April 1 close, the last trading day before the Tesla CEO's more than 9 per cent stake — which makes him the company's biggest shareholder — was made public.
The 50-year-old has more than 80 million followers on the microblogging website.
Twitter's shares jumped 12 per cent in pre-market trading.
"I invested in Twitter as I believe in its potential to be the platform for free speech around the globe, and I believe free speech is a societal imperative for a functioning democracy," Mr Musk says in the filing.
"However, since making my investment I now realise the company will neither thrive nor serve this societal imperative in its current form. Twitter needs to be transformed as a private company," he said in a letter to Twitter chairman Bret Taylor.
"My offer is my best and final offer and if it is not accepted, I would need to reconsider my position as a shareholder," Mr Musk said.
Earlier this week, Mr Musk said he had abandoned a plan to join Twitter's board, just as his tenure was about to start.
Taking the board seat would have prevented him from a possible takeover of the company.
ABC/wires
