Tesla CEO Elon Musk on Thursday made his 'best and final' offer of $54.20 per share in cash to buy 100 per cent of Twitter, in an updated filing with the US Securities and Exchange Commission (SEC). The micro-blogging platform's shares soared nearly 18 per cent in pre-market trading after the news broke.

Musk is offering to "acquire all of the outstanding Common Stock of the Issuer not owned by the Reporting Person for all cash consideration valuing the Common Stock at $54.20 per share," read the filing. Musk says Twitter needs to go private to go through the changes that need to be made.