Billionaire entrepreneur Elon Musk took aim at Twitter Inc with a $43 billion cash takeover offer on Thursday, with the Tesla CEO saying the social media company needs to be taken private to grow and become a platform for free speech.

"I think it's very important for there to be an inclusive arena for free speech," Musk, already San Francisco-based Twitter's second-largest shareholder, said at a TED Talk in Vancouver when asked about his bid.

Musk made the bid on Wednesday in a letter to the board of Twitter — the micro-blogging platform that has become a global means of communication for individuals and world leaders — and it was made public in a regulatory filing on Thursday. His offer price of $54.20 per share represents a 38% premium to Twitter's April 1 close, the last trading day before his 9.1% stake in the social media platform was made public.