https://www.cnet.com/roadshow/news/tesla-saudi-wealth-fund-buyout-source/

Musk on Monday posted on Tesla's website to further explain what's been happening behind the scenes as Tesla potentially prepares to go private. The timeline begins on Aug. 2, when Musk told the board that he wanted to take Tesla private. The board held a meeting (without Musk or his brother Kimbal, who is also a board member), and Musk said he would reach out to some of Tesla's biggest investors to further discuss the issue.

That blog post appears to name Saudi Arabia's sovereign wealth fund as being responsible for the funding that Musk said was "secured" in his tweet. According to the blog, the fund first met with Musk in early 2017 to discuss going private again, and the two parties met multiple times thereafter. The most recent meeting took place on July 31, after the Saudi fund had accumulated a minority stake of about 5 percent.