Tesla Inc. fell after a report said the U.S. Securities and Exchange Commission sent a subpoena to the electric-car maker regarding Elon Musk’s plans to take it private and his claim to have had “funding secured” for the deal.

Wednesday’s drop of as much as 4.5 percent wiped out last week’s advance fueled by Musk’s tweets and reports that Saudi Arabia’s wealth fund bought a stake in the company. Fox Business reported that the SEC sent the subpoena, citing sources it didn’t identify, and said it signaled the agency’s investigation had reached the formal stages.

SEC spokeswoman Judith Burns and a Tesla spokesman declined to comment.

At the center of the controversy is what Musk meant when the chief executive officer tweeted Aug. 7 that he had the funding for a buyout, without providing specifics to back up the claim. Almost a week later, Musk said his confidence was based on conversations with Saudi Arabia’s Public Investment Fund, which first expressed interest in helping take the company private in early 2017.