He said that since his Twitter posts on the possibility of a deal the managing director of the Saudi fund had expressed support for proceeding subject to financial and other due diligence.
Tesla Inc's board (TSLA.O) named a special committee of three directors on Tuesday to negotiate with Elon Musk on taking the electric carmaker private, although it said it was yet to see a firm offer from the company's chief executive.
That assurance caused Tesla's stock to surge 11 percent in one day, boosting the company's market value by more than $6 billion to the dismay investors who had been betting Tesla's shares would decline.
"The special committee has not yet received a formal proposal from Mr Musk regarding any "going private transaction" nor has it reached any conclusion as to the advisability or feasibility of such a transaction", the company said.
"This is why I referred to "funding secured" in the August 7 announcement", he said, referring to his surprise tweet on that date that he was thinking about taking Tesla private. Should Tesla succeed in overcoming the process and any challenges to it though, a deal to take Tesla private could be the largest buyout ever.
Elon Musk is moving forward with his plan to take Tesla private.
Shares in Tesla inched down 0.2 percent in early trading and have now fallen more than 8 percent from highs hit following Musk's tweet last week.
Saudi Arabia's Public Investment Fund (PIF) is known for its technology investments, including the $45bn it has spent in SoftBank Group Corp's Vision Fund.
PIF officials have said in the past that decisions at the sovereign wealth fund are made with care, emphasising corporate governance.
Musk said he will "continue to talk with investors" as he looks into taking the automaker private. Discussing full details on the plan, including the source and nature of the funding, would be "premature" now, he said. At least two lawsuits seeking to become a class action also have been filed against Tesla, alleging Musk broke securities laws by making it sound like all the financing for the buyout had been lined up. What's more, a deal would likely prompt a review but the Committee on Foreign Investments in the US, noted the paper.