Elon Musk Confronts a Fateful Tweet and an ‘Excruciating’ Year

But that funding, it turned out, was far from secure.

Mr. Musk has said he was referring to a potential investment by Saudi Arabia’s government investment fund. Mr. Musk had extensive talks with representatives of the $250 billion fund about possibly financing a transaction to take Tesla private — maybe even in a manner that would have resulted in the Saudis’ owning most of the company. One of those sessions took place on July 31 at the Tesla factory in the Bay Area, according to a person familiar with the meeting. But the Saudi fund had not committed to provide any cash, two people briefed on the discussions said.

Another possibility under consideration is that SpaceX, Mr. Musk’s rocket company, would help bankroll the Tesla privatization and would take an ownership stake in the carmaker, according to people familiar with the matter.

Mr. Musk’s tweet kicked off a chain reaction.

An hour and 20 minutes after the tweet, with Tesla’s shares up 7 percent, the Nasdaq stock exchange halted trading, and Tesla published a letter to employees from Mr. Musk explaining the rationale for possibly taking the company private. When the shares resumed trading, they continued their climb, ending the day with an 11 percent gain.

The next day, investigators in the San Francisco office of the Securities and Exchange Commission asked Tesla for explanations. Ordinarily, such material information about a public company’s plans is laid out in detail after extensive internal preparation and issued through official channels. Board members, blindsided by the chief executive’s market-moving statement, were angry that they had not been briefed, two people familiar with the matter said. They scrambled to cobble together a public statement trying to defuse a mounting uproar over the seemingly haphazard communication.

Mr. Musk said in the interview that board members had not complained to him about his tweet. “I don’t recall getting any communications from the board at all,” he said. “I definitely did not get calls from irate directors.”

Mr. Musk added that he did not regret his Twitter post — “Why would I?” — and said he had no plans to stop using the social media platform. Some board members, however, have recently told Mr. Musk that he should lay off Twitter and focus on making cars and launching rockets, according to people familiar with the matter.

The S.E.C. investigation appears to be intensifying rapidly. Just days after the agency’s request for information, Tesla’s board and Mr. Musk received S.E.C. subpoenas, according to a person familiar with the matter. Board members and Mr. Musk are preparing to meet with S.E.C. officials as soon as next week, the person said.