Elon Musk offers to buy Twitter, says company 'needs to be transformed'

Elon Musk has offered to buy Twitter.

One of the world's richest men delivered a letter to the company with a proposal to acquire all outstanding shares of Twitter for $54.20 each, according to a filing with the Securities and Exchange Commission published Thursday.

The letter, delivered Wednesday, amounts to an offer to take Twitter private, a move that would give Musk greater control of the company. The offer values Twitter at more than $40 billion.

"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," Musk wrote in a letter to Bret Taylor, chairman of Twitter's board of directors, that was included in the SEC filing.

Musk confirmed the offer on Twitter.