A filing with the US Securities and Exchange Commission shows that Musk has offered to buy the company for $43 billion.
It has extraordinary potential. In a letter to the chairman of the company, Musk said he would open it.
The stock of the social media company jumped pre-market.
Musk has offered to buy all of the stock for $54.20 per share in cash. He disclosed in April that he had amassed a 9.2% stake in the company.
In his letter to Taylor, Musk said that he invested in the company as he believed it could be a platform for free speech around the globe.
He said that since making his investment he realized that the company will not thrive or serve this societal imperative in its current form. It needs to be a private company.
Five days later, Musk turned down the position on the board, after the company announced that he had been appointed.
Musk's stock ownership would have been capped at 14.9% if he had joined the board.
This is a developing story.