The offer price also includes the number 420, widely recognized as a coded reference to marijuana.
He also picked $420 as the share price for possibly taking Tesla private in 2018, a move that brought him scrutiny from the SEC.
Musk announced the offer in a filing with the U.S. Securities and Exchange Commission on Thursday.
In a letter to Twitter’s board, Musk said he believes Twitter “will neither thrive nor serve [its free speech] societal imperative in its current form."
He added that Twitter needs to be transformed as a private company.