The case is likely to send shock waves across corporate America and could lead to a re-evaluation of how companies use Twitter to communicate with the investing public.

The S.E.C. said Mr. Musk “knew or was reckless in not knowing” that his statements were false or misleading. “In truth and in fact, Musk had not even discussed, much less confirmed, key deal terms, including price, with any potential funding source,” the S.E.C. said in its lawsuit.

In a statement distributed by Tesla, Mr. Musk said: “This unjustified action by the S.E.C. leaves me deeply saddened and disappointed. I have always taken action in the best interests of truth, transparency and investors. Integrity is the most important value in my life and the facts will show I never compromised this in any way.”

The S.E.C. approached the Tesla chief with an offer to settle the case, according to a person familiar with his thinking, but he refused to negotiate, adamant that he had done nothing wrong. A person briefed on the talks said they fell apart Thursday morning, setting the stage for the S.E.C. to vote on the action.

Tesla itself was not named as a defendant.

A Silicon Valley veteran who joined in founding the company 15 years ago, Mr. Musk is widely regarded by analysts and investors as the creative engine behind Tesla. It has become the most valuable American carmaker, with its stock worth more than $50 billion.